Possible involvement of prostaglandin endoperoxides in cartilage-synovial interactions

The depletion of proteoglycans in cartilage matrix is the beginning of cartilage breakdown. Prostaglandins and related compounds might play an important role in inhibition of cartilage metabolism under arthritic conditions. Prostaglandin endoperoxides, intermediate metabolites of arachidonic acid, are more potent chemical mediators than prostaglandins, but their action can only be demonstrated in cartilage co-incubated with synovial tissue, because they are short-lived and active only within a small restricted space. Human rheumatoid synovialis highly inhibited sulfation of cartilage matrix co-incubated. The inhibition of cartilage metabolism was released by indomethacin added to the co-incubating system, showing its responsiveness to indomethacin. The magnitude of inhibition was time-dependent and substantially greater than that by prostaglandin in cell-free rheumatoid synovial culture media. The results suggest a possible involvement of prostaglandin endoperoxides in potent inhibition of cartilage metabolism under arthritic conditions.     

Mobile intraventricular cyst of the third ventricle treated with stereotactic puncture. Report of a case

A case of a pedunculated arachnoid cyst within the third ventricle is presented. The cyst was small so as not to appear as a significant expanding lesion on CT. The clinical history, however, suggested intermittent increase of the intracranial pressure. On CT there was some widening of the lateral and third ventricles, while the fourth ventricle had normal width. This finding in combination with the clinical history prompted further neuroradiologic examinations, including pneumoencephalography and ventriculography. The presence of a pedunculated mobile cystic lesion within the third ventricle was shown and its nature further elucidated by stereotactic puncture combined with contrast injection into the cyst. After emptying of the cyst, the patient has been free of symptoms during an observation time of 2 years. The diagnostic and differential diagnostic aspects are discussed and the value of traditional neuroradiologic methods emphasized.     

Flow requirements for the Bain breathing circuit during anaesthesia for caesarean section

We studied the relationship between arterial carbon dioxide tension (PaCO2) and fresh gas flow (FGF) during use of the Bain breathing circuit for Caesarean section anaesthesia. Thirty-one patients undergoing Caesarean section were anaesthetised using the Bain circuit with intermittent positive pressure ventilation. The PaCO2 were measured at FGF of 70 ml X kg-1 X min-1, 80 ml X kg-1 X min-1, and 100 ml X kg-1 X min-1. The FGF requirement to maintain a given PaCO2 during Caesarean section anaesthesia is the same as the requirements for nonpregnant subjects, despite the increase in carbon dioxide production associated with pregnancy. This is probably because the total FGF determined by body weight and given during Caesarean section anaesthesia is 15-20 per cent higher than nonpregnant levels, due to the weight gain associated with pregnancy. A FGF of 100 ml X kg-1 of pregnant weight/min maintains PaCO2 of 4.44 kPa predelivery, which is in the desirable range of PaCO2 during Caesarean section.     

Computerized tomography diagnosis of diffuse intraperitoneal metastases after retroperitoneal lymphadenectomy for testicular carcinoma

We report 2 cases of diffuse intraperitoneal metastases from testicular carcinoma following transabdominal retroperitoneal lymphadenectomy. This is an unusual pattern of metastasis for nonseminomatous germ cell tumors and it is believed to be the result of direct seeding from lymphatic leakage secondary to surgery. The value of computerized tomography in diagnosing this entity is emphasized.     

Premenstrual syndrome in Cape Town. Part I. An analysis of 100 consecutive patients

One hundred consecutive patients who attended the premenstrual syndrome clinics at Groote Schuur and Somerset Hospitals were analysed. The incidence did not correlate with age, marital status or parity. Seventy per cent of patients were employed or were full-time students, and 72% had a regular menstrual pattern. The commonest symptoms were irritability, depression and abdominal bloating.     

The clinical efficiency of the Portex in-line blood warmer

The Portex blood warming coil (200/700/000) and water bath (500/111/010) were tested by comparing the body temperatures of two groups of patients undergoing similar operations, but having transfusions of different rate and quantity. The skin and oesophageal temperatures in the massively transfused patients (5-31 units) did not differ significantly from those having minor transfusions (1-5 units). The temperatures were well maintained in both groups. The lowest mean oesophageal temperatures, during the transfusions, were 35.2 +/- 0.2 in the massively transfused patients and 35.4 +/- 0.1 (SEM) in the control group. The warming capacity of the Portex blood warmer was therefore sufficient for our patients. If, however, transfusion rates, higher than those in this study (maximum 96 ml min-1 during the rapid transfusion phase) are needed, a more effective blood warmer may be beneficial.     

Phorbol 12-myristate 13-acetate induces beta-adrenergic receptor uncoupling and non-specific desensitization of adenylate cyclase in human mononuclear leukocytes

Tumour-promoting phorbol esters such as phorbol 12-myristate 13-acetate (PMA) have been reported to modulate beta-adrenergic receptor responses in various cell types, presumably by the activation of protein kinase C. In the present investigation we assessed the effect of PMA on the beta-adrenergic receptor-adenylate cyclase system of human mononuclear leukocytes (MNL). It was found that incubation of MNL with PMA resulted in a time- and concentration-dependent desensitization of isoproterenol-induced adenylate cyclase activity. However, the effect of PMA was not restricted to the beta-adrenergic receptor system, since basal adenylate cyclase activity and histamine-, prostaglandin E1-, 5'-guanylylimidodiphosphate (GppNHp)-, and NaF-stimulated values were also reduced. By contrast, no effect was found on the forskolin-induced adenylate cyclase activity. The inactive phorbol ester, 4 alpha-phorbol 12,13-didecanoate had no effect on adenylate cyclase at all, suggesting that the observed PMA effect was specifically mediated by activation of protein kinase C. The reduced beta-adrenergic response induced by PMA was not associated with a reduced beta-adrenergic receptor number, indicating uncoupling of this receptor from adenylate cyclase. Isoproterenol competition curves for 3H-dihydroalprenolol binding to membranes from untreated and PMA-treated cells demonstrated that the uncoupling was due to a reduced ability of the agonist to promote formation of the guanine nucleotide-sensitive high affinity state of the receptor. The results indicate that PMA may cause desensitization of catecholamine-responsive adenylate cyclase in MNL, and that the major locus of alteration is the guanine nucleotide regulatory protein.     

Vitamin D3 derivatives inhibit the differentiation of Friend erythroleukemia cells

A number of vitamin D3 metabolites inhibit benzodiazepine- and dimethyl sulfoxide-induced differentiation of Friend erythroleukemia cells. The inhibition is dose dependent and occurs at nM concentrations. The order of potency of these compounds is 1,25-dihydroxycholecalciferol greater than 1,25,26-trihydroxycholecalciferol greater than 1,24R,25-trihydroxycholecalciferol greater than 1 alpha-hydroxycholecalciferol greater than 24R,25-dihydroxycholecalciferol greater than 25S,26-dihydroxycholecalciferol. The inhibition is maximal when the vitamin D3 analogs are added together with the inducer, and becomes progressively decreased with delayed addition. These results suggest that the vitamin D3 metabolites may play a regulatory role in erythropoiesis.     

Immunochemical studies of human prolidase with monoclonal and polyclonal antibodies: absence of the subunit of prolidase in erythrocytes from a patient with prolidase deficiency

Prolidase was highly purified from human liver and erythrocytes. NaDodSO4/acrylamide gel electrophoresis revealed that these preparations contained a major protein with MW = 56,000. The mass of prolidase was estimated on gel filtration to be MW = 97,000, for both enzyme preparations. A monoclonal antibody was raised against the liver enzyme and a specific antiserum against the erythrocyte enzyme. The monoclonal antibody (EP-2) recognized prolidase from erythrocytes and liver, in equal proportions. The antiserum also recognized the enzyme from erythrocytes and liver. Immunoprecipitation studies with these antibodies suggested only a single species of prolidase in erythrocytes and liver. Using an immobilized monoclonal antibody (EP-2) as an immunoadsorbent, prolidase was partially purified from crude extracts, and the protein of the partially purified enzyme was identified by immunoblotting using antiserum. A protein band with a MW = 56,000 was demonstrated specifically when crude extracts from the liver and erythrocytes were examined using NaDodSO4/acrylamide gel electrophoresis. The subunit protein was absent in erythrocytes from a patient with prolidase deficiency. We propose that the absence of the subunit is one cause of the prolidase deficiency.     

Comparison of onset and steady-state responses of hearing aids: implications for use of the auditory brainstem response in the selection of hearing aids

Input-output (I/O) functions of hearing aids were measured in response to a 2000-Hz tone burst, having 0.5 ms rise/fall time and 10 ms duration. I/O functions, measured with a hearing-aid analyzer, served as reference conditions. Hearing-aid outputs at onset and during the steady-state portion of the waveform differed; these differences often depended upon stimulus rate. The relation between onset and steady-state estimates of output were not always predictable from hearing-aid attack and release times. These findings indicate that the steady-state output limitation characteristics of hearing aids cannot be estimated from their onset responses. In turn, this suggests that ABR measurements may not provide accurate estimates of the compressive characteristics of hearing aids.