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Biomedical subjects

D Brown

Publications and source records attributed to D Brown.

At least 937 records · Page 52Linked to original sources
PubMed1984

Carbonic anhydrase is associated with taste buds in rat tongue.

A modification of Hansson's histochemical technique was used to reveal carbonic anhydrase activity in mounted cryostat sections of the circumvallate papillae from rat tongue. An intensely positive reaction was found at the level of the neck of the papilla, associated with the taste buds. Lingual glands also contained abundant carbonic anhydrase activity. The presence of carbonic anhydrase in taste buds, as well as our previous observation that it is found in a population of olfactory receptor cells, may indicate a role for the enzyme in gustative and olfactory phenomena.

Animals↗
PubMed1984

Non-A, non-B hepatitis occurring in agammaglobulinaemic patients after intravenous immunoglobulin.

Acute non-A, non-B hepatitis developed in twelve patients with primary hypogammaglobulinaemia during treatment with intravenous gammaglobulin prepared by Cohn fractionation of pooled plasma. The illness was clinically and histologically identical to the short-incubation non-A, non-B, hepatitis observed in haemophilic patients receiving factor VIII concentrates. Most of the patients were symptomless, but 10 months after onset ten of the twelve still had abnormal liver function. The occurrence of non-A, non-B hepatitis in agammaglobulinaemics indicates that humoral mechanisms are not essential for production of hepatocyte necrosis in this infection. This outbreak emphasises the need for a screening test to identify the agent in blood products, and shows that Cohn fractionation of plasma does not always inactivate the agent. Furthermore, the finding that the virus can be transmitted in IgG concentrates suggests either that the general population has a very low level of antibodies to the putative virus or that such antibodies are not virus-neutralising.

Agammaglobulinemia↗
PubMed1984

Parasitic liver damage in lambs with particular reference to the migrating larvae of Ascaris suum.

It has been suggested that the larvae of the pig nematode Ascaris suum is a possible cause of rejection of lambs' livers in the abattoir. However, this assertion was not substantiated in an experimental study in which lambs were dosed with infective A suum eggs. This produced, at the worst, small trivial lesions (up to 2 mm diameter) which would probably have been missed at meat inspection under commercial conditions. No evidence of ascarid lesions was observed in the livers of 5873 lambs and hoggs slaughtered between June and August. The most important causes of rejection were lesions caused by Cysticercus tenuicollis and migrating Fasciola hepatica, and these accounted for 90 and 8 per cent, respectively, of 1337 livers rejected either totally or partially by the meat inspectors.

Abattoirs↗
PubMed1984

Effect of peripheral hearing loss on the masking level difference.

The effects of both symmetric and asymmetric peripheral hearing loss on the masking level difference (MLD) at 500 Hz were studied in 651 subjects with conductive or sensorineural hearing loss and 270 normal controls. The data supported the hypothesis that the modification in MLD due to peripheral hearing loss results from deterioration in threshold in the antiphasic condition. These results provide correction factors for the normal MLD range as functions of boundary frequency of sensorineural loss above 500 Hz and degree of both symmetric and asymmetric sensitivity loss at 500 Hz in both subjects with conductive hearing loss and those with sensorineural hearing loss.

Adolescent↗
PubMed1984

Carbonic anhydrase is present in olfactory receptor cells.

A modification of Hansson 's histochemical technique was used to reveal carbonic anhydrase activity in mounted cryostat sections of rat olfactory mucosa, after glutaraldehyde fixation. A positive reaction that could be inhibited by acetazolamide was found in a population of olfactory receptor cells, whereas the supporting cells were negative. Axons of receptor cells were also positive and could be traced through the cribriform plate to the olfactory bulb.

Animals↗
PubMed1984

Right bundle branch block in complete transposition.

Two of 26 infants with complete transposition presented with complete right bundle branch block in the first year of life, and 10 showed incomplete right bundle branch block. In no instance was the right ventricular conduction anomaly related to surgery or cardiac catheterization and it was not present at birth. The two cases with complete right bundle branch block had prolonged and severe hypoxemia and markedly dilated right ventricles. One had depressed right ventricular function and died after a Mustard procedure from low output syndrome. Whereas incomplete right bundle branch block may reflect right ventricular hypertrophy, it is suggested that complete right bundle branch block in complete transposition may signify right ventricular dysfunction and possibly irreversible changes of the right ventricular myocardium. It may be a sequel of long-term hypoxemia and pressure overload. Once observed, it is perhaps an indication for an alternative surgical approach other than an intra-atrial repair procedure.

Bundle-Branch Block↗
PubMed1984

Process surveillance: auditing infection control policies and procedures.

The infection control team in a university hospital designed, implemented, and evaluated a program to audit infection control policies. Process surveillance techniques of observation and monitoring were used during surveys of patient care areas to evaluate infection control practices. Nineteen unit surveys have been completed in a 2-year period. Analysis of the program has demonstrated it to be an effective method to determine compliance with infection control policies.

Communicable Disease Control↗
PubMed1984

Structural requirements for steroid inhibition of sheep lymphocyte mitogenesis in vitro.

The inhibitory effects of different steroids and related compounds on sheep peripheral blood lymphocytes (PBL) during exposure to the mitogen, phytohemagglutinin (PHA), have been measured by the reduction of [3H]thymidine incorporation into DNA. Dose-response curves showed that a maximum (or near maximum effect) was achieved at a steroid concentration of 12.5 microM. At this dose 19 of 41 compounds significantly reduced thymidine incorporation by activated PBL (P less than 0.01 to P less than 0.001). The greatest reduction was observed with 17-hydroxyprogesterone (-59%, i.e. reduced by 59% compared with vehicle control, 100%) greater than androstenedione greater than epitestosterone greater than estradiol-3-methyl ether greater than 20 alpha-dihydroprogesterone greater than medroxyprogesterone acetate greater than 5 beta-pregnane-3,20-dione greater than 5 alpha-pregnane-3,20-dione (-24%). Among the steroids which showed the greatest inhibitory effect, 6 had a 4-en-3-one group in ring A, 4 had a saturated ring A (pregnane or androstane) and one had a 3-methyl ether group and a phenolic ring A. The wide range of structures represented by these inhibitory steroids suggests that inhibition of lymphocyte mitogenesis involves more than one mechanism.

17-alpha-Hydroxyprogesterone↗
PubMed1984

Thrice weekly lymphoblastoid interferon is effective in inhibiting hepatitis B virus replication.

Six patients with chronic hepatitis B virus (HBV)-induced liver disease were treated with human lymphoblastoid interferon. Daily, alternate day or thrice weekly regimens were employed in two, one and three patients respectively. Thrice weekly intra-muscular injections of 7.5 to 10 megaunits of interferon/m2 appeared to be as effective as daily injections in producing inhibition of HBV replication, were associated with fewer side effects and could be continued for up to 3 months. The effectiveness of this regimen in producing long-term inhibition of viral replication must now be determined.

Adult↗
PubMed1984

Reversible fatigue of stimulus-secretion coupling in the rat neurohypophysis.

Single rat neurointermediate lobes were impaled on a stimulating electrode and continuously perifused with oxygenated medium. The secretion of oxytocin and vasopressin into the medium was measured by specific radio-immunoassays. The temporal profile of vasopressin release during a 20 min period of 13 Hz stimulation was compared with that of oxytocin. The results indicate that although the rate of secretion of both oxytocin and vasopressin declines over 20 min, the extent and time course of this fatigue is different for the two hormones. This difference could not be accounted for by differences in the rate of diffusion of released hormone from the tissue which was similar to the rate of wash-out of [14C]sucrose from the extracellular space in pre-labelled glands. In separate experiments glands were exposed to a prolonged period (60-70 min) of 13 Hz stimulation interrupted by brief silent periods (30 s-2 min duration). Some recovery from the fatigue of vasopressin secretion was evident after even the shortest of these silent periods. In further experiments glands were stimulated electrically for 18, 36, 54 and 72 s at 13 Hz: the order of presentation of the periods of stimulation was randomized between experiments. The vasopressin release rate declined markedly and progressively between 18 and 72 s. In contrast, the oxytocin release rate was relatively uniform throughout 72 s of stimulation. Thus vasopressin secretion is subject to a relatively rapid and dramatic fatigue. The results support the hypothesis that the phasic discharge patterns characteristic of vasopressin secreting neurones optimize the efficiency of vasopressin release from the nerve terminals in the neurohypophysis by avoiding the fatigue of stimulus-secretion coupling that accompanies continual stimulation.

Animals↗
PubMed1984

Capacity of a cis-diammineplatinum[II]-polyglutamic acid complex to cure Trypanosoma congolense infections in mice.

A cis-diammineplatinum(II)-polyglutamic acid complex proved to have marked trypanocidal activity in vivo. When 5 mg of platinum per kg was administered daily for 5 days or when 20 mg of platinum per kg was administered on days 1, 3, and 6, five of five treated Trypanosoma congolense-infected mice were cured. In contrast, cis-platin was ineffective at all doses tested. We believe that the complex has a much higher therapeutic ratio than does uncomplexed drug because it is less toxic.

Animals↗
PubMed1984

In vitro and in vivo cytotoxic activity of native and ricin conjugated monoclonal antibodies to HBs antigen for Alexander primary liver cell carcinoma cells and tumours.

In in vitro and in vivo systems, native or ricin conjugated monoclonal anti-HBs, are capable of inhibiting or slowing the growth of Alexander primary hepatocellular carcinoma cells. Failure of the immune response to this component of the hepatitis B virus may be one permissive factor in the development of some primary liver cell carcinoma in chronic HBV carriers.

Animals↗