Characterization of the histamine H2 receptor structural components involved in dual signaling

We previously demonstrated that the histamine H2 receptor can activate both adenylate cyclase (AC) and phospholipase C (PLC) signaling pathways via separate GTP-dependent mechanisms. We examined whether H2 receptor-specific peptides corresponding to the amino (N) or carboxyl terminus (C) of the second (2i) or third (3i) intracytoplasmic loops or the carboxyl terminal tail (P4iN) could effect histamine- stimulated AC and PLC activity in cell membranes prepared from HEPA cells stably transfected to express the canine H2 histamine receptor cDNA. Tiotidine binding and basal signaling were not altered by the synthetic peptides. H2P2iN, H2P2iC, H2P3iN and H2P4iN did not effect histamine stimulated AC activity although H2P3iC (10(-4) M) significantly inhibited this parameter (65.6 +/- 7.2% of maximal stimulation) (n = 6). Combination of the five peptides (H2P2iN, H2P2iC, H2P3iN, H2P3iC and H2P4iN) abolished histamine stimulated AC activity. Although all of the peptides inhibited histamine-stimulated PLC activity to a moderate degree individually, H2P3iC (10(-4) M) had the greatest effect, decreasing PLC activation to 20.8 +/- 6.3% of maximal stimulation (IC50 = 7.5 X 10(-7) M) (n = 6). H2P3iC and the peptide combination did not alter, forskolin, GTP gamma s or epinephrine-stimulated AC activity nor GTP gamma s and vasopressin-stimulated PLC. These studies demonstrate that both the second and third intracytoplasmic loops of the histamine H2 receptor are linked to separate signaling pathways in a differential manner.

Psychological and behavioral issues of a cohort of Puerto Rican HIV/AIDS patients

The current study describes the psychological and behavioral issues of a cohort of Puerto Rican HIV/AIDS patients. Differences in the depression mean score were determined and the predictor variables of depression among a cohort of Puerto Rican HIV/AIDS patients were also identified.

DESIGN

Cross-sectional survey of a longitudinal cohort (N=1,500).

METHODS

The setting of this study was the Immunologic Clinic and the Dr. Ramón Ruiz Arnau University Hospital in Bayamón, Puerto Rico. The sample was composed initially of 58 patients who had completed the Beck Inventory depression test (alpha Cronbach=0.93) and who were registered at the HIV/AIDS Central Registry between April 1995 and July 1996.

RESULTS

Women had higher depression scores than men. High education groups (>12th grade) had lower depression scores than low education groups. Patients reporting heterosexual practices had higher depression score than patients without that practice. A multiple linear regression showed that predictors variables of the depression score were gender and education.

CONCLUSIONS

A wide spectrum of psychological and behavioral features were present within the HIV/AIDS sample, including depression.

Profile of HIV patients with and without bacterial endocarditis

Bacterial endocarditis (BE) is a serious medical condition seen in the injecting drug users (IDU) with or without HIV. Studies report a low prevalence of BE in HIV/AIDS patients and the clinical manifestations have been considered non-specific making early diagnosis difficult. The HIV Registry in our Center has recruited 1500 HIV/AIDS cases since May 1992. We decided to review and compare the clinical and epidemiological variables of patients admitted to the Registry with BE (23 pts) and without. Fever, sweats and weight loss were seen most frequent in BE patients as well as meningitis and pneumonia. The majority of the patients were IDU. Staphylococcus aureus was the most common pathogen. The tricuspid valve was the most affected valve. Mild insufficiency was the rule. The mortality in BE patients was higher than in the total group. The triad of IDU, the described constitutional signs and symptoms and coexisting meningitis and/or pneumonia, in the HIV/AIDS patient, should alert the physician to the presence of BE particularly in the outpatient setting were a more aggressive diagnostic approach should probably be attempted.

Gender-related differences in the spectrum of HIV disease in the Bayamón area, Puerto Rico

We compare prevalence (by actual presence or history of condition) rates of selected AIDS-defining conditions across genders in a sample of 1,498 HIV-infected participants who visited our health service facilities between mid 1992 and early 1996. The comparisons were performed globally (considering all subjects) and on a subsample of participants whose most probable mode of infection with HIV was through (self-reported) use of injecting drugs. Global analysis revealed no significant differences across genders for any of the conditions considered; the most prevalent condition being Pneumocystis carinii pneumonia. Subsample-specific analysis (injecting drug users), however, revealed that women from this subgroup were likelier to have (present or by history) at least one AIDS-defining condition; they were also significantly likelier to specifically report candidiasis and Pneumocystis carinii pneumonia.

123Iodo-MK-801: a spect agent for imaging the pattern and extent of glutamate (NMDA) receptor activation in Alzheimer's disease

Glutamate, and the NMDA glutamate receptor, may be involved in Alzheimer's Disease (AD). Reductions in NMDA receptors are found in AD, possibly contributing to memory deficits. However the NMDA receptor is involved in excitotoxicity, which may play a role in cell death and the production of neurofibrillary tangles in AD; although with lower levels of glutamate than occur in cerebral ischaemia. Therefore reductions in the NMDA receptor may worsen memory deficit in AD, but increased stimulation of the receptor may contribute to the progress of the disease. MK-801 has been used to image excessive glutamate activation following ischaemia in rats. However, it is unclear how effective MK-801 is in conditions with lower levels of glutamate release. This study attempts to gain insight into the utility of the tracer in these conditions, exploring glutamatergic mechanisms in AD. It describes the retention and elimination of 123iodo-MK-801 in five AD and five control subjects, comparing this to regional cerebral blood flow (rCBF). The initial uptake of 123I-MK-801 is dominated by delivery of the ligand. However, despite significant reductions in rCBF in the AD patients, there is no significant difference in the uptake of 123I-MK-801. This suggests increased retention of 123I-MK-801 in the AD patients. In addition the washout of 123I-MK-801 was less in the AD patients, again suggesting increased retention, although this only reached significance in one region. Theses data hint at possible increases in NMDA activation in AD but ultimately 123I-MK-801 does not provide a sufficiently accurate measurement to demonstrate this conclusively. Further NMDA ligands are now at a late stage of development and may provide more conclusive answers to the role of glutamate in AD.

Psycho social and clinical spectrum of HIV/AIDS injecting drug users in Bayamón, Puerto Rico

OBJECTIVES

To describe the demographic characteristics, the risk related practices, and the clinical and immunological features of Puerto Rican HIV injecting drug users (IDU's).

DESIGN

Cross-sectional survey of a longitudinal cohort (N=1,500).

METHODS

The HIV Central Registry at the Universidad Central del Caribe has been recruiting HIV/AIDS patients attending the Immunologic Clinic and the University Hospital Ramón Ruiz Arnau since may 1992. 1500 patients have been interviewed and a record including demographic, risk related, clinical and immunologic data has been created for each one of them. Chi square and t-tests were performed to assess the potential significant differences of the TDU's vs the non-IDU's.

RESULTS

57.1% of the HIV/AIDS patients were IDU's. Most of them were males, had a lower education level, with an age fluctuating between 27 to 36 years old and most of them were unemployed. Most IDU's reported to have had heterosexual relations. With regard to the clinical spectrum, Pneumocystis carinii pneumonia (PCP) was the only indicative condition associated with injecting drug use (IDU), as well as bacterial endocarditis, chronic diarrhea, night sweats and idiopathic fever. The spectrum of vulnerabilities of IDU's is larger than that of non-IDU's, with regard to psycho-social, behavioral and clinical features. These vulnerabilities can limit their access to services and render their compliance to treatment more difficult.

Reactivity of 87 monoclonal antibodies against tissues in vivo and resting and irradiated endothelial cells in vitro

Altered expression of vascular endothelial cell (EC) surface antigens in response to irradiation is one of the early events of radiation-induced damage. Using flow cytometry, we investigated the immunocytochemical reactivity of a blind panel comprising 87 mAbs submitted to the endothelial section of the 6th International Workshop on Human Leukocyte Differentiation Antigens with irradiated and resting human dermal microvascular endothelial (HDME) and EA cell lines. Monolayers of irradiated cells received a single 5 Gy dose of 72 h prior to staining but were otherwise treated the same as resting cells. For comparative purposes we have also examined the immunohistochemical reactivity of the mAb panel with EC in ovarian tumour, Wilms' tumour and human placenta. In the flow cytometry experiments 42 and 44 mAbs stained HDME and EA cells respectively and while no antibody stained irradiated but not unirradiated cells, upregulation was seen for CD31, CD34, CD141 and CD146 in irradiated cells. The upregulation of thrombomodulin (CD141) is noteworthy since it is a marker of EC damage and thus may be a useful reagent in investigations of vascular injury. Comparison with tissue staining showed that 21 mAbs were reactive with at least one tissue but not with either EA or HDME cells. Nine mAbs showed no cross reactivity with tissue and of these one reacted with EA cells only.

Alzheimer's disease in the United Kingdom: developing patient and carer support strategies to encourage care in the community

Alzheimer's disease is a growing challenge for care providers and purchasers. With the shift away from the provision of long term institutional care in most developed countries, there is a growing tendency for patients with Alzheimer's disease to be cared for at home. In the United Kingdom, this change of direction contrasts with the policies of the 1980s and 90s which focused more attention on controlling costs than on assessment of the needs of the patient and carer and patient management. In recent years, the resources available for management of Alzheimer's disease have focused on institutional care, coupled with drug treatment to control difficult behaviour as the disease progresses. For these reasons, the current system has led to crisis management rather than preventive support--that is, long term care for a few rather than assistance in the home before the crises occur and institutional care is needed. Despite recent innovations in the care of patients with Alzheimer's disease, the nature of the support that patients and carers receive is poorly defined and sometimes inadequate. As a result of the shift towards care in the community, the informal carer occupies an increasingly central role in the care of these patients and the issue of how the best quality of care may be defined and delivered is an issue which is now ripe for review. The objective of this paper is to redefine the type of support that patients and carers should receive so that the disease can be managed more effectively in the community. The needs of patients with Alzheimer's disease and their carers are many and this should be taken into account in defining the quality and structure of healthcare support. This paper shows how new initiatives, combined with recently available symptomatic drug treatment, can allow patients with Alzheimer's disease to be maintained at home for longer. This will have the dual impact of raising the quality of care for patients and improving the quality of life for their carers. Moreover, maintaining patients in a home environment will tend to limit public and private expenditure on institutional care due to a possible delay in the need for it.

The Belfast Cord Blood Bank

The first cord blood bank in the British Isles was established in Belfast in June 1993. Cord blood (CB) is rich in haematopoietic progenitor cells and has been used successfully as a substitute for bone marrow transplants in over 200 patients world-wide. Most have received CB from a histocompatible sibling, but reports include several unrelated HLA matched transplants. In addition to the cryopreservation of 400 units of donated CB in the Cord Blood Bank, we have stored eight CB collections from siblings of children with leukaemia in Northern Ireland. A pilot study in collaboration with the maternity unit in the Mater Infirmorum Hospital confirmed the feasibility of a CB banking programme and highlighted many issues relating to Good Manufacturing Practice (GMP). The authors describe experience of collecting 824 units of CB over three years and discuss a few of the wider implications of this innovation in the management of patients requiring myeloablative therapy.

Longitudinal changes in cognitive function and regional cerebral function in Alzheimer's disease: a SPECT blood flow study

In Alzheimer's disease (AD), SPECT imagining of regional cerebral blood flow (rCBF) has emphasized deficits in the posterior association cortex. Previous studies have shown an association between these deficits and cognitive performance, both on overall cognitive tests and more specific tests such as praxis and language. Frontal deficits have been reported in more severe patients. This has led to the conclusion that the deficit in AD, at least with functional neuroimaging, starts in the posterior association cortex, and later in the disease process "spreads" to involve the frontal cortex. This study set out to measure, in a group of AD patients, the change over time of cognitive performance and the pattern of functional deficit measured by neuroimaging. Change in function was measured using 99TCm-HMPAO and SPECT and change in cognitive function using the CAMCOG. Two time points were used, 0 and 2 years. Twenty-four patients satisfying the DSM-III R criteria for probable AD were studied, nine of whom were subsequently diagnosed as having AD at post-mortem. The most striking finding was the effect that decreases in frontal lobe function had on cognitive function. A similar study by the same group, using the same techniques and many of the same patients but at only one time point, showed a correlation between cognitive function and rCBF in the parietal and posterior temporal lobes. This suggests that as AD patients deteriorate from unaffected to mild or moderately affected, the posterior association cortex exerts the greatest effect on cognitive deficit. In this longitudinal study, we found, using a MANOVA, that there were significant decreases over time for all the cortical regions studied, but that no region decreased significantly more than any other. In addition we found a correlation between change in frontal rCBF and change in cognitive function (both overall cognitive function and the CAMCOG sub tests of language and praxis). These data suggest, in contrast to the previous study, that as the disease progresses from mild or moderate to moderate or severe, the frontal cortex exerts the greatest effect on cognitive decline. These data support the concept of the deficit in functional imaging spreading from posterior to anterior as the disease progresses. However, both the initial pattern of deficit and the change over time were very heterogeneous when examined qualitatively. A posterior to anterior spread is the predominant pattern for the group as a whole, but individual patients, and possibly groups of patients, may well show alternative patterns.

Signet-ring carcinoma in Crohn's disease presenting as a neck mass

We report a case of signet cell carcinoma of the colon in a patient with Crohn's disease. Signet cell carcinoma, also termed linitis plastica, is an unusual malignancy of the colon and is rarely associated with Crohn's disease. In general, metastatic disease is evident at the time of diagnosis, and the prognosis is uniformly poor. The radiographic, endoscopic, and histological features are discussed.

Meniscal injuries associated with acute anterior cruciate ligament tears in alpine skiers

We reviewed the records of 315 patients receiving an arthroscopically assisted stabilizing procedure for an acute anterior cruciate ligament injury incurred while alpine skiing to evaluate associated meniscal injuries. Meniscal injuries were classified by type, location, and treatment of the tear. Of the 317 knees operated on, all demonstrated an anterior cruciate ligament tear at arthroscopy. Ninety-eight percent of the injuries (310) were diagnosed within 3 days of injury, and 97% (307) were reconstructed within 28 days of injury. All tears occurred in the intrasubstance of the ligament; 32% were isolated injuries and 68% were combined with other injuries. In 159 patients with 170 meniscal tears 141 of the tears (83%) were lateral and 29 (17%) were medial. The injury triad of anterior cruciate ligament-medial collateral ligament-lateral meniscus was seen nine times as often as the anterior cruciate ligament-medial collateral ligament-medial mensicus combination.

Technetium-99m labelling of bis-oxime ligands

The synthesis and labelling of a new bis-amide-oxime ligand E,E-2,9-bis(hydroxyimino)-4,7-diaza 5,6-dioxodecane (AdO) with 99mTc has been achieved. Protein binding, partition coefficient and tissue distribution of this complex and two related bis-amine-oxime ligands is reported. The biodistribution of the complexes are disappointing with only limited brain and myocardial uptake. Structures for the complex are postulated.

Deficits in iodine-labelled 3-quinuclidinyl benzilate binding in relation to cerebral blood flow in patients with Alzheimer's disease

A loss of acetylcholine is one of the most consistent neurochemical findings in Alzheimer's disease (AD) post-mortem, but the debate concerning receptor abnormalities is unresolved. The aim of this investigation was to measure the density of acetylcholine muscarinic receptors in AD patients at various stages in the disease (N = 8) by synthesising a radio-iodinated version of quinuclidinyl benzilate QNB, a potent muscarinic antagonist. Deficits were identified by comparison with a control data set obtained from four elderly volunteers and then compared to the deficit in total functional activity in the same brain regions measured using the cerebral perfusion tracer technetium-99m hexamethylpropylene amine oxime. Iodine-123 (R,R)quinuclidinyl benzilate (QNB) was synthesised using a CuI assisted nucleophilic aromatic exchange reaction. 160 MBq of the radioligand (specific activity 400 Ci/mmol: dose 90 ng/kg) was administered to each subject. Diagnosis of AD was made using the CAMDEX and DSMIIIR criteria with a physical examination, full blood screen, CT and chest X-ray. All subjects were scanned at 21 h post injection on an SME810 emission tomograph. 123I(R,R)QNB activity in the controls was found to be consistent with the known distribution of muscarinic receptors with no activity in the cerebellum and low activity in the thalamus. In the AD patients deficits in 123I-QNB binding which exceeded the corresponding total functional regional perfusion deficit were not found in six of the patients and were observed only in the two most severely affected patients, both of whom were untestable on the cognitive battery.(ABSTRACT TRUNCATED AT 250 WORDS)

An outbreak of Norwalk-like gastroenteritis associated with contaminated drinking water at a caravan park

During the 1989 Christmas holiday period, a large outbreak of gastroenteritis occurred among persons staying at a caravan park in southern New South Wales. Review of local hospital records found that 77 per cent of patients presenting with infective diarrhoea between 29 December and 3 January had stayed at the caravan park. In a retrospective cohort study we compared rates of illness among caravan park patrons exposed to different water sources. Stools were tested for pathogens and convalescent sera for viral antibodies. Rain and reticulated river water sampled from the caravan park were tested for bacteria and viruses. Of 351 persons interviewed at the caravan park, 305 (87 per cent) reported an illness characterised by diarrhoea, vomiting and abdominal pain. Of 196 persons who used reticulated river water for drinking or ablutions, 175 (89 per cent) became ill compared with 47 of 72 persons (65 per cent) who did not use this water (relative risk 1.4, 95 per cent confidence interval 1.2 to 1.6). The outbreak was probably caused by a 27-28 nm small round structured virus found in the stool from one ill person. High levels of faecal coliforms in the reticulated river water and enterovirus in sediment samples suggest that the outbreak was caused by sewage contaminating the reticulated river water through a break in the pipe directly over the underground water tanks. To prevent such outbreaks, poor water and sewerage system layouts should be avoided and nonpotable water should be clearly labelled. Where feasible, all camping-ground water should stem from town supplies.

Abnormalities in rCBF and computed tomography in patients with Alzheimer's disease and in controls

The pattern of abnormal distribution of the single photon emission computed tomography (SPECT) cerebral blood flow tracer 99m-technetium-hexamethylpropyleneamine oxime (99Tcm-HMPAO) was investigated in 14 patients with clinically diagnosed Alzheimer's disease (AD) who subsequently had post-mortem confirmation of the disease and also in 14 elderly control subjects. These abnormalities were compared with computed tomography (CT) scans to investigate the degree to which the focal SPECT deficits were due to atrophy. The results show that SPECT imaging with 99Tcm-HMPAO and CT scanning both have a higher incidence of abnormality in AD patients than in controls and that the difference between patients and controls is greater with SPECT than with CT. Frontal SPECT and CT abnormalities in moderate/severe Alzheimer's disease occur as frequently as temporal/occipital abnormalities but the latter are rare in control subjects. Around 50% of the SPECT deficits occur in CT normal brain regions, showing that atrophy is not the sole cause of SPECT deficits.

Revisional Surgery for Failed Gastric Restrictive Procedures for Morbid Obesity

As part of the Adelaide Obesity Surgery Study, we have reviewed all patients who have undergone revisional surgery. Of the 31 0 trial patients, 63 (20%) had revisions 1-69 (median 32) months following their original surgery-30% of all 105 gastrogastrostomy (GG) operations, 22% of 106 gastroplasty (GP) procedures, and 9% of 99 gastric bypasses (GB). Failure was due to stomal dilatation, 11% of all trial patients (71% of GG revisions), stomal stenosis, 6% (52% of GP revisions) and staple dehiscence, 4%. There was no mortality and a low hospital morbidity. Long-term success was only 23% (follow-up at least 3 years) and was achieved at considerable expense (3 reversals, 10 further revisions, 44 endoscopic procedures). Revisional surgery was successful in 45% of patients with stomal dilatation or dehiscence but in only 17% with stenosis. Overall, the most successful operation was revision of, or conversion to, gastric bypass (58% success rate), compared with gastroplasty (24%) and gastrogastrostomy (25%). Our long-term results following revisional surgery were disappointing, particularly for stenosis, and most failures followed revision to GG or GP. Roux-en-Y gastric bypass is the procedure of choice when considering revision.