Characterization of the polA gene of Streptococcus pneumoniae and comparison of the DNA polymerase I it encodes to homologous enzymes from Escherichia coli and phage T7

The DNA sequence of the polA gene of Streptococcus pneumoniae was determined, and the DNA polymerase I encoded by the gene was purified to homogeneity. Determination of the amino-terminal amino acid sequence of the protein showed it to correspond to the Mr 99,487 polypeptide predicted from the nucleotide sequence. The mRNA transcript was mapped with respect to its sites of initiation and termination in the DNA. Inasmuch as the mRNA begins only two nucleotides before the first codon, it lacks a typical ribosome binding site. Nevertheless, 500 molecules of the protein are produced per cell. Like the Escherichia coli DNA polymerase I, the protein from S. pneumoniae has 5'- and 3'-exonuclease as well as polymerase activities, and it also undergoes a single cleavage on mild proteolysis. Alignment of the two different polymerase I proteins shows 40% of their amino acid residues to be identical. Homology is evident also with the DNA polymerase encoded by phage T7 gene 5. In addition, the amino-terminal regions of the bacterial polymerase I proteins are homologous to the separate 5'-exonuclease protein encoded by phage T7 gene 6. Analysis of the patterns of homology suggests that the bacterial polymerase I may represent the accretion of at least six separate genetic regions.

The muscarinic agonist pilocarpine inhibits DNA and interferon-gamma synthesis in peripheral blood mononuclear cells

Lymphocyte basal DNA synthesis and proliferative responses to phytohemagglutinin (PHA) showed a dose-dependent (5 X 10(-5)-5 X 10(-3) M) inhibition by the muscarinic agonist pilocarpine, in contrast to the basal enhancing effect produced by the M2 muscarinic-nicotinic agonist carbachol. The effect of pilocarpine was reversed by both atropine (1 X 10(-6) M) and pirenzepine (1 X 10(-7)-1 X 10(-8) M), M1-M2 and M1 muscarinic antagonists, respectively. The effect of pilocarpine may thus be specific for the M1 muscarinic receptor. Pilocarpine also inhibited interferon-gamma (IFN-gamma)-PHA induced production, but was unable to reverse the pokeweed mitogen (PWM)-induced DNA synthesis. Distinct immunoregulatory activities are suggested for cholinergic muscarinic receptors M1 and M2.

What radiologic technology educators should know about due process of law

Student rights and the responsibility of educators in providing adequate protection of those rights continues to be a major concern in all educational programs. Due process of law, as it pertains to the schools, outlines specific procedures that should be followed when disciplinary action must be taken involving a student. Applying these guidelines assures fundamental fairness and reasonableness.

Papillomaviruses in human skin warts and their incidence in an Argentine population

Human papillomavirus genomic types present in human warts of an Argentine population were studied. HPV DNA from single warts was obtained using an alkaline extraction procedure that resulted in a clean DNA preparation, which could be analyzed with several endonucleases. This method was used to isolate and insert the HPV DNAs of two genomic types into the Bam HI site of the pBR322 plasmid. Restriction maps of both HPV DNAs were constructed. According to these maps, one of the genomic variations was identical to HPV1a and the other to HPV2a. The incidence of HPV2 and of HPV1 in different types of skin warts was studied by a dot blot hybridization assay. Twenty-two out of 28 common warts were positive for HPV2 and negative for HPV1; four were positive for HPV1 and negative for HPV2 and two were negative for both. Five out of six plantar warts were positive for HPV1, and one was negative for both. Three out of seven filiform warts were positive for HPV2, three were positive for both probes, and one was negative for both. Southern blot analysis of HPV2 positive samples indicated that 80% were HPV2a and 20% another subtype not yet characterized. All plantar warts contained HPV1a. Msp I/Hpa II restriction analysis confirms previous results indicating that HPV1a DNA is partially methylated, while no evidence of methylation was found for HPV2a DNA.

Clinical significance of abnormalities of the gastrointestinal tract detected by abdominal ultrasound

In order to define the clinical significance and the need for further clinical work-up in patients where abnormalities of the stomach or bowel are found by ultrasound, we performed a prospective study on 100 patients with such findings. Of all patients, 35% were found to have a malignant tumor, 73% had a diagnosis as made by reference methods which was probably (18%) or definitively (55%) related to the US finding. Eighteen percent had definitive false positive findings, in 9% no final diagnosis was obtained. Thus, a positive predictive value of 80% was calculated for the US finding of a mass or a target sign related to bowel or stomach in US. The positive predictive value was lowest for target signs related to the bowel (75%) and highest for bowel conglomerates (100%). Patients with target signs of the stomach, bowel conglomerates, or masses were more likely to have malignant disorders (72%) than those with target signs related to the bowel (16%). We conclude from this study that the ultrasound finding of a target sign or a mass related to stomach or bowel has a high clinical relevance and should in any case worked up by appropriate investigations when clinical consequences are possible.

Streptococcus pneumoniae polA gene is expressed in Escherichia coli and can functionally substitute for the E. coli polA gene

The Streptococcus pneumoniae polA+ gene was introduced into Escherichia coli on the recombinant plasmid pSM31, which is based on the pSC101 replicon. Extracts of E. coli polA5 mutants containing pSM31 showed DNA polymerase activity, indicating that the pneumococcal DNA polymerase I was expressed in the heterospecific host. Complete complementation of the E. coli polA5 mutation by the pneumococcal polA+ gene was detected in excision repair of DNA damage.

Angiotensin II regulates interferon-gamma production

An extensive literature links the immune responses to neuroendocrine regulation. We have examined the effects of the neuropeptide hormone angiotensin II on the production of the immunomodulatory lymphokine interferon-gamma (IFN-gamma). Angiotensin II (10(-6)-10(-8) M) stimulated (three- to fivefold) the IFN-gamma production in human blood lymphocytes obtained from normal individuals. At 10(-9) M angiotensin II stimulation disappeared and was reestablished at physiological concentrations of the neuropeptide (10(-10)-10(-11) M). Stimulation by angiotensin II was compared with the classical effect of the lectin phytohemagglutinin, and it was seen that both actions are mediated by external calcium (as they are blocked by EGTA 2.5 mM) and that the stimuli follow different kinetics, reaching the steady state at 6 h with angiotensin II and later (18 h) when the lectin was used. The effect of angiotensin II over the IFN-gamma production was blocked by its analog sarcosine 1-isoleucine 8-angiotensin II, showing the specificity of angiotensin II action. These findings demonstrate a selective biological regulation of IFN-gamma production by angiotensin II and suggest another regulation pathway of immune responses.

A prospective study of intraoperative histologic antrum and corpus boundary in patients undergoing highly selective vagotomy for duodenal ulcer

The results of the present study demonstrate that, at the level of the proximal branch of Crow's foot of Latarjet, parietal cells are found, and therefore, it must be sectioned when performing highly selective vagotomy. At the level of the distal branch, antral mucosa is found. At the level of the middle branch, in almost one-half of the instances, parietal cells are found, and its section must be evaluated with gastric emptying studies.

Chlamydia trachomatis detection in adolescents. A comparison of direct specimen and tissue culture methods

We compared tissue cell culture isolation with the Microtrak fluorescent monoclonal antibody direct specimen test for detection of endocervical Chlamydia trachomatis in an inner-city population of sexually active Black and Hispanic adolescent girls. Of the 95 patients screened, C. trachomatis was identified in 26.3%. The sensitivity of the direct specimen test was 91.7%, and its specificity was 98.6%. The positive predictive value was 95.6%, and the negative predictive value was 97.2%. No significant difference was found between Blacks (28.6%) and Hispanics (24.1%) in the incidence of endocervical C. trachomatis, nor was the use of an oral contraceptive significantly associated with the diagnosis of C. trachomatis (p greater than 0.10). Neisseria gonorrhoeae was isolated in 8.4% of the patients. The direct specimen test appears to be an accurate and convenient method of screening sexually active adolescent girls for genital C. trachomatis. Further study is needed to determine if an oral contraceptive increases the risk of Chlamydia infection in adolescents.

Cardiovascular manifestations in systemic lupus erythematosus. Prospective study of 100 patients

One hundred consecutive female patients with active systemic lupus erythematosus (SLE) were studied from the cardiovascular point of view by means of non invasive methods. Seventy percent of the cases presented some type of cardiovascular anomaly. Seventy four percent of the resting electrocardiograms were abnormal as well as 72% of the M mode echocardiograms and 55% of the cardiac X ray series. The most frequent observed complications were: pericarditis and or pericardial effusion (39%), arterial hypertension (22%), ischemic heart disease (16%), myocarditis (14%), congestive heart failure (10%), pulmonary hypertension (9%), valvular heart disease (9%), pleural effusion (7%) and cerebro vascular accident (3%). We analyzed each one of these complications and found of special interest the high incidence of ischemic heart disease which is more frequent than has been hitherto reported. Ischemic heart disease was observed in two types of patients: a) Those with long term steroid therapy. In these, the mechanism seems to be an atherosclerotic disease probably induced by the chronic use of steroids. The management of these cases do not differ from other types of coronary heart disease due to atherosclerosis. b) Those with frank episodes of vasculitis in whom the basic mechanism is an inflammatory process of the coronary arteries and its treatment is fundamentally that of the vasculitis. We consider necessary to study routinely all patients with SLE through non invasive cardiological methods.

Spontaneous rupture of an intra-aortic balloon pump

Circulatory assistance with an intraaortic balloon pump is not free from risks and complications. Among the latter, rupture is extremely rare. We report a case of spontaneous rupture of an intraaortic balloon, which occurred after 29 h of counterpulsation in a patient with cardiogenic shock following an acute myocardial infarction. The probable cause of the rupture was the constant abrasion and eventual perforation of the balloon membrane by a sharp calcified aortic plaque.

Tuberculoma of the pons

Images

Hysteroscopy in the diagnosis of endometrial carcinoma: case report

The incidence of endometrial carcinoma is particularly high in postmenopausal women. Screening techniques are not yet satisfactory. Postmenopausal anatomic physiologic changes in the genitalia may prevent visualization and exploration of the uterine cervix. A case report is presented of an 87-year-old woman with a 6-month history of genital bleeding. Severe vaginal stenosis prevented diagnostic curettage, even under adequate anesthesia. To perform the indicated hysteroscopy, a panendoscope had to be employed for direct visualization of the cervix and uterine cavity. Selective biopsy specimens revealed endometrial adenocarcinoma. The hysteroscopy technique is easy to learn. However, if the patient's physician has not acquired this experience, a urologist, who must necessarily use endoscopy extensively, can be of great help in the evaluation fo gynecologic patients with uterine problems similar to those described in this report.

Secretory IgA content in human normal and tumoral bronchial mucosa in vitro

Secretory IgA-S content was evaluated in vitro in human normal and tumoral bronchial mucosa from 39 cases. In 75% of the cases, IgA-S production by tumoral tissue was higher than the levels found in control populations. On the other hand, IgA-S synthesis by normal bronchial tissue of patients with lung tumors, particularly with squamous cell carcinoma, was increased in comparison with patients free of neoplastic bronchopulmonary disease, in 30% of the cases. Comparing tumorous tissue with normal mucosa from the contralateral bronchus of the same patient, marked differences in IgA-S patterns were observed. Regarding the results obtained, we could consider the measuring of IgA-S in bronchial mucosa as a valuable diagnostic aid in patients with suspect pulmonary masses.

Temporary liver transplantation in acute liver failure

The ability of a heterotopic graft to prolong life in animals dying in hepatic coma due to liver necrosis has never been definitely established. Acute hepatic failure was produced in 15 dogs by an hour of total interruption of the hepatic blood supply. Nine dogs received an intrathoracic hepatic homograft concurrently. Nontransplanted dogs died within 21 hours in hepatic coma, while transplanted dogs survived significantly longer (P less than .001). In all transplanted dogs, biological signs of hepatic failure were corrected in 24 hours. In four animals, the graft was removed on the fifth postoperative day. Two of those survived for 10 and 15 days respectively with normal hepatic function. These results demonstrate that a temporary heterotopic liver transplant is able to support life during the acute, normally lethal phase in dogs with massive liver necrosis.

A pressor substance in the cerebrospinal fluid of normotensive and hypertensive patients

A pressor polypeptide was isolated from the cerebrospinal fluid of normotensive and hypertensive patients. Pharmacologically it behaves like angiotensin I. A very significant correlation (r = 0.83, P < 0.001) was found between the concentration of this polypeptide and the blood pressure of essential hypertensive patients.

Arrangement of Macromolecular Components in Erythrocyte Membranes and Their Relation to Bound C3 and C4

The purpose of this study was to examine the distribution of a ntigenic components in the intact erythrocyte (E) membrane (M) and their relation to bound C3 and C4. Rabbit antisera were prepared by immunization with whole sheep EM. Immunoelectrophoresis (IEP) of M solubilized with 2.5% Triton X-100 (T) revealed one β2 line and two to four α-β1 lines. M solubilized by sonication in 10% n-butanol and fractionated by ultracentrifugation in 24% sucrose (Morgan, T. H. and Hanahan, D. J., Biochemistry, 5: 1050, 1966) yielded a light fraction rich in carbohydrates and lipids, having high affinity for T and β2 position on IEP after treatment with T, and a heavy fraction rich in protein, migrating in the α-β1 IEP area. Absorption of anti-EM with intact E removed its hemagglutinating activity and its capacity to react with the β2 component without altering its anti α-β1 activity.