Third- and fourth-generation implantable cardioverter defibrillators: current status and future development

Implantable cardioverter defibrillator (ICD) therapy has become the mainstay of therapy for patients with a history of sudden cardiac death or life-threatening ventricular arrhythmias. The current generation of ICDs used for secondary prevention combines features for tachycardia reversion with demand ventricular pacing, antitachycardia pacing, programmable shock therapy, and tachycardia events memory. Although demand pacing and defibrillation is indicated for primary prevention usage of ICDs, the application of antitachycardia pacing modes is more controversial. High energy cardioversion and defibrillation shocks remaining the mainstay of sudden death prevention will be redefined as more effective defibrillation shock modes and lead systems are developed. Fourth-generation ICD systems accomplished a significant reduction of device size and almost universal success using an endocardial lead configuration and pectoral implant. A variety of new directions of ICD therapy in clinical practice such as primary prevention applications and the adjunctive role of antiarrhythmic drug therapy are currently being examined in clinical trials. The concepts underlying initiation of tachyarrhythmias are being studied to develop new approaches to tachycardia prevention. These include rate support, subthreshold stimulation, and multiple site pacing. The current developments of ICD therapy promise continued growth of this technology.

Characterization of a psychrotrophic Clostridium causing spoilage in vacuum-packed cooked pork: description of Clostridium algidicarnis sp. nov

A Clostridium species causing spoilage of vacuum-packed refrigerated pork was isolated and characterized. The unknown organism differed phenotypically from other clostridial species usually associated with spoilage. Phylogenetic analyses based on 16S rRNA gene sequencing demonstrated that the psychrotroph represents a distinct line of descent within the genus Clostridium. It is proposed that the organism be classified as a new species of the genus Clostridium, Clostridium algidicarnis.

Evaluation of butorphanol and cyproheptadine for prevention of cisplatin-induced vomiting in dogs

Cisplatin was administered at a dosage of 50 mg/m2 of body surface to 69 dogs with various neoplasms. Dogs were randomly assigned to receive antiemetics according to 1 of the following 5 protocols: group 1, no antiemetic (control, n = 45 treatments); group 2, 0.4 mg of butorphanol/kg of body weight (n = 52 treatments); group 3, 0.2 mg of butorphanol/kg (n = 19 treatments); group 4, 2 mg of cyproheptadine/kg (n = 48 treatments); and group 5, 1 mg of cyproheptadine/kg (n = 10 treatments). Randomization was performed for each dog prior to each treatment. Butorphanol was administered IM immediately after completion of cisplatin infusion. Cyproheptadine was given orally 12 to 14 hours before and again immediately before cisplatin administration. The proportion of dogs that vomited in group 1 was 40 of 45 (89%). Butorphanol at a dosage of 0.4 mg/kg proved highly effective in preventing cisplatin-induced vomiting, reducing the proportion of dogs that vomited (10/52, 19%) compared with the control group.

Surgical treatment of thymoma in cats: 12 cases (1987-1992)

Twelve cats with thymoma were treated by surgical excision of the tumor alone. None of the cats received radiotherapy or chemotherapy. Two cats died or were euthanatized during the immediate postoperative period: 1 because of postsurgical hemorrhage, and the other because of an associated fungal pleuritis. None of the remaining 10 cats developed evidence of local tumor recurrence or metastases. Six of the cats were alive after follow-up periods ranging from 6 to 36 months (mean, 21 months; median, 21 months). Three cats were euthanatized 18 months, 32 months, and 45 months following surgery for unrelated problems, and 1 cat died as a result of trauma sustained 62 months postoperatively. Myasthenia gravis developed postoperatively in 2 of the cats.

Homozygous Tangier disease and cardiovascular disease

Decreased levels of plasma high density lipoprotein (HDL) cholesterol have been associated with premature cardiovascular disease (CVD). Tangier disease is an autosomal co-dominant disorder in which homozygotes have a marked deficiency of HDL cholesterol and apolipoprotein (apo) A-I levels (both < 10 mg/dl), decreased low density lipoprotein (LDL) cholesterol levels (about 40% of normal), and mild hypertriglyceridemia. Homozygotes develop cholesterol ester deposition in tonsils (orange tonsils), liver, spleen, gastrointestinal tract, lymph nodes, bone marrow, and Schwann cells. Our purpose was to assess the prevalence of CVD in Tangier disease. We reviewed published clinical information on 51 cases of homozygous Tangier disease, report 3 new cases and provide autopsy information on 3 cases. Mean (+/- S.D.) lipid values of all cases were as follows: total cholesterol 68 +/- 30 mg/dl (32% of normal), triglycerides 201 +/- 118 mg/dl (162% of normal), HDL cholesterol 3 +/- 3 mg/dl (6% of normal) and LDL cholesterol 50 +/- 38 mg/dl (37% of normal). The most common clinical finding in these subjects (n = 54) was peripheral neuropathy which was observed in 54% of cases versus < 1% of control subjects (n = 3130). CVD was observed in 20% of Tangier patients versus 5% of controls (P < 0.05), and in those that were between 35 and 65 years of age, 44% (11 of 25) had evidence of CVD (either angina, myocardial infarction or stroke) versus 6.5% in 1533 male controls and 3.2% in 1597 female controls in this age group (P < 0.01). In 9 patients who died, 2 died prior to age 20 of probable infectious diseases, 3 of documented coronary heart disease at ages 48, 64, and 72, 2 of stroke at ages 56 and 69, one of valvular heart disease, and 1 of cancer. In three autopsy cases, significant diffuse atherosclerosis was observed in one at age 64, moderate atherosclerosis and cerebral infarction in another at age 56, but no atherosclerosis was noted in the third case who died of lymphoma at age 62. In one patient with established coronary heart disease, none of the lipid lowering agents used (niacin, gemfibrozil, estrogen or lovastatin) raised HDL cholesterol levels above 5 mg/dl. However, these agents did have significant effects on lowering triglyceride and LDL cholesterol levels. Our data indicate that there may be heterogeneity in these patients with regard to CVD risk, that peripheral neuropathy is a major problem in many patients, and that CVD is a significant clinical problem in middle aged and elderly Tangier homozygotes.(ABSTRACT TRUNCATED AT 400 WORDS)

Prognosis after surgical excision of cerebral meningiomas in cats: 17 cases (1986-1992)

Long-term follow-up information was obtained for 17 cats with cerebral meningiomas treated by surgical excision. Three cats died or were euthanatized in the immediate postoperative period: 2 cats, because of brain herniation and 1 cat, because of acute renal failure. In the remaining 14 cats, most clinical signs resolved within 1 week of surgery. Three cats (21.4%) had confirmed or presumed local tumor recurrence. Two of these cats developed recurrent neurologic signs, and died or were euthanatized at 3 and 9 months, respectively, after surgery. One cat was euthanatized for an unrelated problem 72 months after surgery, and on postmortem examination, had a recurrent meningioma at the surgery site. The remaining 11 cats (78.6%) did not develop evidence of local tumor recurrence within follow-up periods ranging from 18 to 47 months (median, 27 months).

Effect of protamine sulfate on the permeability properties of the mammalian urinary bladder

Protamine sulfate (PS, an arginine-rich protein of molecular weight 5,000) has been reported to affect the ionic permeability of gallbladder epithelium, the permeability of cultured epithelial cells to mannitol, and the permeability of endothelial cell layers to albumin. Although the effect of PS has been widely investigated, the mechanism of its action on membrane permeability is presently unknown. The effect of PS on the rabbit urinary bladder epithelium was studied using both transepithelial and intracellular microelectrode techniques in conjunction with equivalent circuit analysis. The addition of 100 micrograms/ml of PS to a NaCl-containing mucosal solution caused (over a 40-min period) a large increase in the transepithelial conductance (Gt) and a transient hyperpolarization of the transepithelial voltage (Vt) followed by a depolarization of Vt. This secondary depolarization of Vt was not present if the mucosal solution was a KCl or a K-gluconate Ringer. The PS-induced increase in Gt was due to an increase in the apical membrane permeability to both cations (Na+ or K+) and anions (Cl- or gluconate). Further studies revealed the following features of the PS-induced conductance. (i) Trypsin inhibits the PS effect; however, this was due to PS hydrolysis by trypsin and not a membrane effect. (ii) Mucosal PS partially inhibited the PS-induced apical membrane conductance. (iii) The ability of PS to increase the membrane conductance was enhanced when the apical membrane potential was cell interior negative. (iv) The rate of conductance change (at any given membrane potential) was a saturating function of the PS concentration. This finding suggests that PS must interact with a membrane binding site before it can induce a change in the membrane conductance. (v) Lanthanum inhibited the PS-dependent conductance by two different mechanisms. One was as a reversible blocker of the PS-induced conductance. The other was by inhibiting the interaction between PS and a membrane binding site. A kinetic model is developed to describe the steps involved in the increase in membrane conductance.

Coronary risk factors in middle-aged men as related to smoking, coffee intake and physical activity

The relationship between lifestyle and coronary risk factors in blood was investigated in 165 middle-aged men. Plasma fibrinogen, serum triacylglycerols (TG), and apolipoprotein B (apo B) were higher, and high density lipoprotein cholesterol (HDLc) lower in smokers (n = 69) than in non-smokers (n = 96). By linear regression analysis there was a significant positive association between degree of smoking and either total cholesterol (TC), apo B, or plasma fibrinogen, whereas smoking was inversely related to HDLc. Smoking and coffee intake were positively correlated with an atherogenic index, reflecting the balance between low and high density lipoproteins. Sedentary men (n = 59) had higher mean TC, apo B, and atherogenic index than physically active men (n = 104). Smokers used salt more often than non-smokers. Physically active men used vegetables more often than sedentary men. Combining several habits into a "bad habit" score gave a high level of significance for its association with TC, apo B, and the atherogenic index. The results indicate that lifestyle may influence several blood factors involved in atherosclerosis development.

Treatment by digital amputation of subungual squamous cell carcinoma in dogs: 21 cases (1987-1988)

Malignant digital tumors were diagnosed in 62 dogs during a 1-year period. Twenty-one (33.9%) of the dogs had subungual squamous cell carcinoma. Each of these dogs had involvement of single digits. Sixteen (76.2%) of the dogs with squamous cell carcinoma were large-breed dogs, and 15 (71.4%) had predominantly black coats. Labrador Retrievers (n = 5, 23.8%) and Standard Poodles (n = 3, 14.3%) were the most commonly represented purebreeds. None of the dogs had evidence of metastases prior to treatment. All 21 tumors were treated by amputation of the involved digit. Histologic evidence of neoplastic bone invasion was found in 15 of the 21 amputated digits (71.4%). Local tumor recurrences were not observed. Only 1 dog developed documented metastatic disease; this dog was euthanatized because of pulmonary metastases 5 months after surgery. At the time of this report, 9 dogs (42.9%) were alive with no evidence of disease (median, 26 months after surgery), and 11 dogs (52.4%) had died or were euthanatized (median, 20 months after surgery). The cause of death in 7 dogs was known to be unrelated to squamous cell carcinoma, and the cause of death in 4 dogs was unknown. The 1-year and 2-year survival rates were 76.2% and 42.9%, respectively.

Treatment of dogs with osteosarcoma by administration of cisplatin after amputation or limb-sparing surgery: 22 cases (1987-1990)

Twenty-two dogs with appendicular osteosarcoma were treated by amputation (n = 17) or limb-sparing surgery (n = 5). All dogs were given cisplatin (60 mg/m2 of body surface, IV) at 3-week intervals, beginning 1 week after surgery. Number of cisplatin treatments ranged from 1 to 6. Survival data for the 22 dogs were compared with survival data from a historical control group consisting of 162 dogs with appendicular osteosarcoma treated by amputation alone. Median survival time for the 22 dogs given cisplatin was estimated to be 46.4 weeks, and 1- and 2-year survival rates were estimated to be 45.5 and 20.9%, respectively. Survival time was significantly (P less than 0.0001) longer for treated dogs than for control dogs. Statistically significant relation was not found between survival time and number of cisplatin treatments. Three dogs were alive with no evidence of disease at the time of reporting. Of the remaining 19 dogs, 14 (73.4%) were euthanatized for problems documented to be related to metastases. Nine (47.4%) dogs were euthanatized because of bone metastases, and 5 (26.3%) were euthanatized because of pulmonary metastases. The proportion of dogs euthanatized because of bone metastases was significantly (P less than 0.0001) higher for treated than for control dogs. Median survival times for dogs developing bone and lung metastases were estimated to be 51.2 weeks and 21.2 weeks, respectively; however, this difference was not statistically significant. One local tumor recurrence was observed among dogs that had limb-sparing surgery. Significant difference in survival time was not observed between dogs that had limb-sparing surgery and dogs that underwent amputation.

Prognosis for dogs with appendicular osteosarcoma treated by amputation alone: 162 cases (1978-1988)

Long-term follow-up information pertaining to 162 dogs with appendicular osteosarcoma treated by amputation alone was collected from 17 veterinary institutions. The majority (72.5%) of dogs died or were euthanatized because of problems documented to be related to metastases. The first clinically apparent sites of metastasis were the lungs (60.8% of total), the skeleton (5.2%), or both (4.6%). A Kaplan-Meier survivorship distribution was plotted on the basis of available survival time data in all 162 dogs. The mean and median survival times were estimated to be 19.8 and 19.2 weeks, respectively, and the 1- and 2-year survival rates were estimated to be 11.5 and 2.0% respectively. Statistically significant relationships were not found between survival time and reporting institution, gender, site of primary tumor, whether the primary tumor was proximally or distally located, whether the primary tumor was located in the forelimb or hind limb, whether presurgical biopsy was performed, and whether death was tumor related. A significant (P less than 0.01) quadratic relationship was found between age and survival time. Survival time was longest in dogs 7 to 10 years old and was shorter in older and younger dogs.

Effects of four preparations of 0.05% chlorhexidine diacetate on wound healing in dogs

Four chlorhexidine diacetate (CHD) antiseptic wound lavage preparations were evaluated in vivo to determine their effects on second intention wound healing in the dog in vitro to determine their relative antibacterial activity against Staphylococcus intermedius. Chlorhexidine was diluted to 0.05% in sterile water, 0.9% sodium chloride, lactated Ringers solution (LRS), and LRS that was allowed to form a precipitate with CHD. Control solutions included sterile water and LRS. There were no significant differences in wound contraction or epithelialization. All 0.05% CHD preparations provided 100% bacterial kill.

Determinants of a genotoxic effect of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in human diploid fibroblasts

The induction of micronuclei was studied in human diploid fibroblasts incubated in the presence of the tobacco-specific nitrosamine NNK. We used four fibroblast strains having a high capacity of O6-alkylguanine DNA alkyltransferase (13.0-23.3 pmol O6-methylguanine repaired per 8 x 10(6) cells) and four strains that showed no detectable repair capacity. Incubation with NNK doubled the frequency of micronuclei in repair-deficient cells but failed to evoke any effect in the proficient cell strains. Control experiments were performed with the direct methylating agent MNNG and in the presence of inhibitors of either metabolic activation or alkyltransferase. The results showed that the genotoxicity of NNK is dependent on the relationship between its metabolic activation and the constitutive DNA repair. This supports earlier findings that low constitutive levels of O6-alkylguanine DNA alkyltransferase may increase susceptibility to lung cancer after exposure to DNA methylating agents.

Modifying the request behaviour of clinicians

AIM

To evaluate whether the feedback of laboratory use and cost data to clinicians modifies their request behaviour.

METHODS

Over two years the effect of monthly feedback of clinical chemistry test use and revenue expenditure to three consultant physicians on their clinical chemistry and haematology requesting patterns was evaluated. Two physicians who received no information served as controls.

RESULTS

Feedback over one year led to an immediate and sustained decrease of 15%, 27%, and 21% in clinical chemistry requests (p less than 0.01), tests (p less than 0.001), and revenue expenditure (p less than 0.001), respectively, and a 10% reduction in haematology tests (p less than 0.05) per outpatient visit. These changes persisted in the six months after the feedback was stopped.

CONCLUSIONS

These results suggest that feedback of laboratory data to clinicians modifies their request behaviour and that supplying clinicians with information on what they do can influence the way they make decisions.

Spinal lymphoma in cats: 21 cases (1976-1989)

Medical records of 21 cats with spinal lymphoma were reviewed. All cats were evaluated for neurologic deficits, although 85% of cats necropsied had multicentric disease. Eighty-one percent of cats had hind limb paresis. Results of FeLV tests were positive in 84.2% (16/19) of the cats, and 68.7% (11/16) of the cats had leukemic bone marrow. Spinal lymphoma was confirmed by necropsy in 13 cats, by examination of a biopsy specimen in 1 cat, and by examination of cells aspirated from an epidural lesion in 2 cats. In the remaining 5 cats, a presumptive diagnosis was made on the basis of neurologic examination findings, positive FeLV test results, and leukemic bone marrow. Nine cats were treated with chemotherapy alone. The complete remission rate was 50% in 6 cats given cyclophosphamide, vincristine, and prednisone. The median duration of complete remission was 14 weeks. Complete remissions were not observed in 3 cats given only corticosteroids. A single cat treated by laminectomy and postoperative chemotherapy had a prolonged remission (62 weeks). At necropsy, lymphoma of the CNS was limited to the vertebral canal in 10 of 13 cats; 2 cats had malignant tissue in the brain and vertebral canal, and in the remaining cat, the tumor extended into the brachial plexus. Most tumors extended over multiple vertebral bodies, and 4 cats had more than 1 level of spinal cord involvement. The lymphoma was high-grade lymphoblastic or immunoblastic type in all cats.

In vitro assay of nuclear uptake of doxorubicin hydrochloride in osteosarcoma cells of dogs

A rapid, simple chemosensitivity assay, assessing tumor cell nuclear uptake of doxorubicin hydrochloride, was evaluated in 16 dogs with appendicular osteosarcoma. Doxorubicin was administered to dogs in 5 biweekly treatments, and surgical resection was performed after the second or third treatment. The chemosensitivity assay was performed on biopsy specimens from all dogs before chemotherapy. It was repeated on tissue from resected tumors, and tumors were evaluated histologically to determine the degree of necrosis resulting from chemotherapy. Disease-free and total survival time correlated significantly (P less than 0.05 in both cases) with the degree of postchemotherapy necrosis of the primary tumors. Significant correlation was not apparent between the percentage of tumor cells with nuclear uptake of doxorubicin (in either biopsy or resection samples) and disease-free or total survival time. The percentage of cells with nuclear uptake of doxorubicin in surgically resected tumors correlated significantly (P less than 0.05) with percentage of necrosis.

HeLa-LAV, an epithelial cell line stably infected with HIV-1

An HeLa-LAV cell line was established by infecting and subcloning previously described CD4-expressing HeLa cells with HIV-1. Cells of this line stably synthesize all major HIV proteins, release infectious particles of HIV-1, but do not die even after long term culture. More than 90% of the cells express the envelope protein gp120 on the surface. The cells can be easily and efficiently labeled with 51chromium, and exhibit a low spontaneous release. Because they are susceptible to killing by allogeneic cytotoxic T cells (CTL) when targeted to gp120, they ought to be a useful source of target cells in any kind of HIV-specific killing assays. The cells may also help studies on HIV replication in non-lymphatic/non-monocytic cells. The HeLa-LAV cell line will be freely available from the AIDS Research and Reference Reagent Program.

Bispecific antibodies that mediate killing of cells infected with human immunodeficiency virus of any strain

Although AIDS patients lose human immunodeficiency virus (HIV)-specific cytotoxic T cells, their remaining CD8-positive T lymphocytes maintain cytotoxic function. To exploit this fact we have constructed bispecific antibodies that direct cytotoxic T lymphocytes of any specificity to cells that express gp120 of HIV. These bispecific antibodies comprise one heavy/light chain pair from an antibody to CD3, linked to a heavy chain whose variable region has been replaced with sequences from CD4 plus a second light chain. CD3 is part of the antigen receptor on T cells and is responsible for signal transduction. In the presence of these bispecific antibodies, T cells of irrelevant specificity effectively lyse HIV-infected cells in vitro.

Treatment of posttraumatic carinal stenosis by balloon dilation during thoracotomy in a cat

A cat with posttraumatic stenosis of the terminal part of the thoracic portion of the trachea and carina was successfully treated by balloon dilation of the stenosis during thoracotomy. Thoracotomy was performed at the right fifth intercostal space, and the stenosis was dilated, using a balloon-tipped catheter passed through an endotracheal tube. A 6-week course of orally administered corticosteroids was instituted after surgery. Balloon dilation during thoracotomy is a technically simple procedure for treatment of stenosis of the thoracic portion of the trachea.

Craniolateral approach to the humerus with transection of the brachialis muscle

Six fractures of the midshaft or distal third of the humerus were repaired through a modified craniolateral approach in which the brachialis muscle was transected rather than retracted to improve exposure of the bone. The approach simplified fracture reduction and fixation. Normal fracture healing and excellent limb function resulted in each case.

Feedback of laboratory usage and cost data to clinicians: does it alter requesting behaviour?

In a 1 year prospective study we evaluated the effect of feedback of laboratory data on the requesting behaviour of physicians in general medicine. Data on within-hours and out-of-hours clinical chemistry laboratory usage and revenue expenditure for inpatients and outpatients, expressed in terms of clinical workload, were supplied monthly to a group of three consultant physicians in general medicine. With these data the physician could monitor his performance over a period of time and compare it with that of his peers. Two consultants in general medicine who received no information served as controls. Over a period of 6 months, there was a 25%, 13% and 18% decrease in tests (P less than 0.01), requests (P less than 0.05) and revenue expenditure (P less than 0.01) per outpatient visit, respectively, in the intervention group of physicians following the introduction of feedback when compared to their baseline period and to the control group. The decrease (P less than 0.01) was in the commonly requested and 'seemingly cheap' tests. There was no significant change in laboratory use and expenditure on inpatients. The feedback of laboratory data was acceptable to the physicians, raised their awareness of laboratory usage and costs and decreased laboratory workload and expenditure.

Giant cell tumor of the accessory carpal bone in a dog

A 4-year-old Springer Spaniel was referred because of a 6-week history of progressive left forelimb lameness. A marked pain response was elicited by palpation over the left accessory carpal bone. Radiography revealed a lytic, markedly expansile lesion of the accessory carpal bone. The bone was excised, and pancarpal arthrodesis was performed. Histologic examination of the excised bone revealed giant cell tumor. At 14 months after surgery, the dog was using the limb normally. Radiography of the carpus revealed satisfactory progression of the arthrodesis, and thoracic radiographs were negative for metastases.

Preoperative measurement of canine primary bone tumors, using radiography and bone scintigraphy

Specimens of 20 canine primary bone tumors (18 osteosarcoma, 2 fibrosarcoma) were examined to compare the maximal axial length of gross tumor with the length of the lesion seen on preoperative radiographs and 99mTc methylene diphosphonate bone scintigraphic images. Radiographs defined the length of the tumor to within +/- 10% of the gross measurement for 6 (30%), underestimated it for 12 (60%), and overestimated it for 2 (10%) specimens. Bone scintigraphy defined tumor length within +/- 10% for 8 (40%), underestimated it for 1 (5%), and overestimated it for the remaining 11 (55%) specimens. Use of radiographic evaluation alone could result in underestimation of the diaphyseal extent of a primary bone tumor, with risk of incomplete resection. Bone scan images tend to overestimate tumor length and, therefore, may provide safer resection guidelines.

Bone scintigraphy in the initial evaluation of dogs with primary bone tumors

Bone scintigraphy was performed as part of an initial diagnostic evaluation of 70 dogs admitted with primary bone tumors during a 2-year period. Tumors involved major long bones of the appendicular skeleton and included 62 osteosarcomas, 6 fibrosarcomas, and 2 chondrosarcomas. All dogs were free of radiographically detectable pulmonary metastases. Bone scintigraphy was not of value in distinguishing among various types of primary tumors. One dog with an ulnar chondrosarcoma had a scintigraphically detectable occult osseous metastasis or synchronous primary tumor, and 1 dog with osteosarcoma had a scintigraphically detectable lymph node metastasis. Pulmonary metastases were not detected scintigraphically. Of the 70 dogs, 44.3% had areas of increased isotope uptake associated with nonneoplastic disease processes.

Immunoglobulin lambda gene rearrangement can precede kappa gene rearrangement

Immunoglobulin genes are generated during differentiation of B lymphocytes by joining gene segments. A mouse pre-B cell contains a functional immunoglobulin heavy-chain gene, but no light-chain gene. Although there is only one heavy-chain locus, there are two light-chain loci: kappa and lambda. It has been reported that kappa loci in the germ-line configuration are never (in man) or very rarely (in the mouse) present in cells with functionally rearranged lambda-chain genes. Two explanations have been proposed to explain this: (a) the ordered rearrangement theory, which postulates that light-chain gene rearrangement in the pre-B cell is first attempted at the kappa locus, and that only upon failure to produce a functional kappa chain is there an attempt to rearrange the lambda locus; and (b) the stochastic theory, which postulates that rearrangement at the lambda locus proceeds at a rate that is intrinsically much slower than that at the kappa locus. We show here that lambda-chain genes are generated whether or not the kappa locus has lost its germ-line arrangement, a result that is compatible only with the stochastic theory.

Liquid chromatographic determination of 2',3'-dideoxyguanosine in human plasma

A rapid assay for 2',3'-dideoxyguanosine (ddG) in human plasma has been developed. The ddG was first extracted from human plasma using solid phase extraction. The extract containing ddG was then assayed with liquid chromatography using an ODS column and a mobile phase of 9% methanol in pH 6.8 phosphate buffer. The overall method had good accuracy (within 2%), linearity (r = 0.9998), sensitivity (LOD = 1.8 ng, S/N = 3) and recovery (greater than 99% for 5-50 micrograms ddG per ml plasma).

Subcapsular hematoma of the liver during pregnancy

We have reported a case of subcapsular hematoma of the liver, diagnosed and observed by ultrasonography, in association with the HELLP syndrome. The patient's condition improved with conservative management, but the hematoma was clearly shown to last for more than 12 weeks, which shows the need for extended postpartum follow-up and appropriate patient consultation.

Daily living with COPD. Self-help skills to improve functional ability

Although patients with chronic obstructive pulmonary disease (COPD) experience many problems as a result of their disease, they can use numerous strategies to maximize functional ability and maintain health. Patients with COPD should be encouraged to learn more about their disease and use commonsense approaches to management. Referral to a pulmonary rehabilitation program that offers comprehensive assessment, individualized treatment, and access to support groups is also valuable. Rehabilitation programs often result in an improved capability for daily activities and a better quality of life.

Arterial embolization in patients with renal carcinoma

The literature concerning embolization of the renal artery in patients with renal cell carcinoma is reviewed. Based on this review it is concluded that the method is useful in this patient group as it will facilitate the surgical procedure if nephrectomy is performed afterwards. Used as a palliative method, embolization reduces haematuria. It was not possible to draw conclusions concerning survival rates or eventual immuno-stimulating effects of embolization.

Microencapsulation of emulsified oil droplets by in-situ vinyl polymerization

This paper reports on the preparation and evaluation of microcapsules formed by the polymerization of methyl methacrylate in the presence of an oil/water emulsion. The oil phase was composed of an alkane (n-decane or hexadecane) and the oil/water emulsions were stabilized by a variety of emulsifiers. Both oil-soluble and water-soluble initiators were used and the monomer was introduced by either dissolving it in the oil or by feeding it through the water. The primary objective of the work was to study the effects of both formulation and process variables on the morphological characteristics of the polymer/oil composite particle. Our experimental findings indicate that it is not a trivial task to assure that the polymer is formed at the interface in such a way that it envelopes the oil droplet. It was found that the type of emulsifier used is crucial in determining the success of the encapsulation process.

Translation affects immunoglobulin mRNA stability

When termination codons were introduced into exons of the gene for Ig mu chain, steady-state levels of mu mRNA were reduced, both at the pre-B cell stage and at the plasma cell stage. A termination codon in the variable region gene segment and a termination codon in the second exon of the constant region gene segment had effects of similar magnitude. When the termination codon was deleted, the original level of mRNA was restored. The rate of mu gene transcription was the same whether or not a termination codon was present. Therefore, the termination codons must reduce the amount of the mRNA by reducing its stability. Since the introduced termination codons prematurely terminate translation and, in so doing, change the ribosome load on the mRNA, we conclude that mu mRNA stability is conferred in part by ribosomal protection from enzymatic degradation. We propose that the differences in mu mRNA stability during B lymphocyte differentiation are due to different amounts of ribosomes available for translation.

Correction of nonuniform attenuation in cardiac SPECT imaging

Correction for photon attenuation in cardiac SPECT imaging using a measured attenuation distribution with an iterative expectation maximization (EM) algorithm and an iterative Chang algorithm were compared with the conventional filtered backprojection and an iterative EM algorithm without attenuation correction. The attenuation distribution was determined from a transmission computed tomography study that was obtained using an external collimated sheet source. The attenuation of the emitting photons was modeled in the EM algorithm by an attenuated projector-backprojector that used the estimated attenuation distribution to calculate attenuation factors for each pixel along each projection and backprojection ray. Results from a heart-lung phantom study and a 201Tl patient study demonstrated that the iterative EM algorithm with attenuation correction provided improved image quality in terms of reduced streak artifacts and noise, and more accurate quantitative information in terms of improved radioactivity distribution uniformity where uniformity existed, and better anatomic object definition.

Epidural opioids as anaesthesia for extracorporeal shock wave lithotripsy in two patients with cardiac disease

Two patients with cardiac disease underwent Extracorporeal Shock Wave Lithotripsy (ESWL) in the Dornier HM3 machine. In order to minimize cardiovascular changes, epidural opioids (fentanyl 100 micrograms in 10 ml saline was used in one patient and meperidine 50 mg in 10 ml saline in the other patient) were used as an alternative to either general anaesthesia or epidural local anaesthesia. Both patients displayed haemodynamic stability, remained pain-free and experienced no complications. Epidural opioids proved a suitable form of anaesthesia for ESWL in these patients.

Anaesthesia for extracorporeal shockwave lithotripsy at the Victorian Lithotripsy Service--the first 300 patients

A prospective survey was undertaken of the anaesthesia for the first 300 patients at the Victorian Lithotripsy Service. The majority (71.7%) were not hospitalised on site, including four quadriplegics and two ASA grade IV patients. Two hundred and eighty-three (94.3%) patients received continuous lumbar epidural anaesthesia, sixteen (5.3%) received general anaesthesia and one received a spinal anaesthetic. Eighty-two patients (27.3%) underwent ancillary procedures at the time of extracorporeal shockwave lithotripsy. The most common intraoperative complications were hypotension (72 patients, 25.4%) and shivering (39 patients, 13.8%). Arrhythmias occurred in nine (3%) patients. There was a 90% patient follow-up rate and the most common postoperative complication was backache (101 patients, 37.4%). The problems of anaesthesia for extracorporeal shockwave lithotripsy are discussed. Epidural anaesthesia offers a number of advantages for this procedure and proved very suitable for the majority of patients.

Determination of the optimum filter function for SPECT imaging

An observer study was performed in order to evaluate several filters used in SPECT imaging. The filters were applied to the simulated projection data of a uniform activity density cylinder which contained a cold, spherical lesion, 2 cm in diameter. The data incorporated the effects of the detector and scatter response functions, photon attenuation, and noise. Reconstructed transaxial images were used in 2AFC and ROC observer studies testing lesion detectability. In the 2AFC experiment, the Hanning filter scored lowest and did not show a optimum cutoff frequency. The Butterworth filter performed better and showed a well-defined optimum cutoff frequency at 0.15 cycles/pixel. The Metz filter performed as well as the optimum Butterworth but did not show an optimum power factor. In the ROC study, a high power Metz filter demonstrated an ROC curve of lower Az index and different shape from a lower power Metz filter and the optimum Butterworth filter.

Evidence for a high attack rate and efficacy of erythromycin prophylaxis in a pertussis outbreak in a facility for the developmentally disabled

During an outbreak of pertussis in residents and staff of a facility for the developmentally disabled, 149 persons had laboratory evidence of Bordetella pertussis infection; 130 (87%) reported respiratory illness. Infection rates (IR) in affected wards ranged from 6% to 91%. Most residents were adolescents and adults and had received a full course of diphtheria-tetanus toxoids-pertussis (DTP) vaccine; IRs increased with increasing time after the last DTP dose in fully vaccinated residents. The IR was lower in residents on wards where erythromycin treatment/prophylaxis was started two or fewer weeks after the onset of illness in the first case on the ward (IR, 16%), compared with four or more weeks after onset (IR, 75%; P less than 10(-6)). Respiratory symptoms were milder in ill residents treated within seven days of onset of illness. Although B. pertussis transmission was substantial, erythromycin treatment of patients and prophylaxis of exposed persons was effective in decreasing transmission and disease severity. Carbamazepine toxicity occurred in seven (19%) of 37 residents when carbamazepine was administered with erythromycin.

Anorexia tardive: a diagnosis of exclusion?

An elderly female patient is described in whom rapid severe weight loss appeared initially to be of psychogenic origin and self-induced. A diagnosis of late-onset anorexia nervosa or anorexia tardive was made when early investigations revealed no abnormality apart from changes that were consistent with malnutrition, and when typical behavioural and psychological factors together with putative psychodynamic issues were revealed. At first, nasogastric feeding was beneficial, but a stormy hospital course ensued. Further investigations revealed the presence of neoplastic disease which at post-mortem examination proved to be small-cell carcinoma of the lung.