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Biomedical subjects

G Crane

Publications and source records attributed to G Crane.

8 recordsLinked to original sources

Role of the capsulo-ligamentous structures in rotation and combined flexion-rotation of the lumbar spine.

We carried out experiments on whole cadaveric lumbar spines in order to determine the role that each of the capsulo-ligamentous structures play in axial rotation in the neutral position and in the flexed position. Eight specimens were first tested intact, then after division of all the apophyseal joint capsules between L1 and the sacrum. Another five specimens were also first tested intact, then after division of the supra- and interspinous ligaments and yellow ligament, and finally after cutting the posterior longitudinal ligament and posterior annulus at each level as well. The results show that there is considerable variation in the axial rotation of the lumbar vertebrae within the same spine and across different spines. The apophyseal joint capsules limit rotation both in neutral and flexed positions. In flexion, the amplitude of rotation in the lumbar spine is reduced. Of the capsulo-ligamentous structures, it is the posterior annulus and the posterior longitudinal ligament that seem to play the more important role in limiting axial rotation while the spine is flexed.

Adult

Analysis of HLA class II allogenotyping in Australian aborigines and Papua New Guinea populations.

Human leukocyte antigen (HLA) class II allogenotyping has been applied to investigate the polymorphism of the DRB, DQB1, DQB2, DQA1, and DQA2 genes in Aborigines from the East Coast of Australia and in Melanesians from the Papua New Guinea North-East Coast and Highlands. Three new DR/DQ arrangements were observed, DRw14/DQB1-2b/DQA1-1a and DRw5Nauru/DQB1-3a/DQA1-2 (n Australian Aborigines), and DRw5Nauru/DQB1-1a/DQA1-1b (in Madang). DQA2 and DQB2 allogenotyping with TaqI and PstI digested genomic DNA revealed little polymorphism among the Papua New Guineans, with DQA2-Xa1 and DQB2-Xb1 the most common alleles in all the groups. However, the presence of DQA2-Xa2 in Papuans and Australian Aborigines reflects the degree of admixture with Caucasoids while the DQA2-Xa4 allele in Madang is probably a marker of Mongoloid origin.

Asian People

AIDS and infection control in dermatologic surgery.

In summary, the AIDS epidemic has created many new questions for the dermatologist, with no clear answers. As dermatologic surgery is increasing in most dermatology practices, the dermatologic surgeon must take a careful look at his office techniques and educate his personnel on the proper handling of blood and body fluids. The medical and ethical issues raised by the AIDS epidemic are complex, with new issues being raised as more is learned about the disease. The adage "do no harm" should be kept in mind in the counseling, diagnosis, and treatment of HIV-infected individuals.

AIDS Serodiagnosis

The genetic basis of hyperreactive malarious splenomegaly.

Hyperreactive malarious splenomegaly (HMS) represents an abnormal immune response to recurrent malaria, characterized by excessive production of both IgM and IgG antibodies. It has both a racial and a familial distribution in various parts of the world. Immune responses to many foreign antigens, including those of malaria, are under genetic control of the major histocompatibility locus (MHC), through the influence of HLA antigens on regulatory T-lymphocyte activity. It is therefore likely that this region also contains the genetic determinants for HMS, which would be reflected in associations between HMS and particular HLA antigens or haplotypes. Genetic studies of the Watut people of Papua New Guinea have not shown any association between HMS and a wide range of red cell and serum polymorphisms. However, HMS in this group is associated with the class II HLA antigen DR2, and with high levels of HLA heterozygosity. Formal genetic analysis of family data also points to a sex-linked gene as a further determinant of overresponsiveness to malaria in the Anga. These findings suggest that more than one genetic system may be involved in the development of HMS, and that the combined effects of several genetic determinants may be responsible for the extraordinarily high frequency of HMS found in the Upper Watut Valley.

Humans

Dipsogenic effects of intra and extracellular thirst stimuli before and after chronic DFP treatment.

The water intake of rats was observed following subcutaneous administration of intra and extracellular thirst stimuli (hypertonic saline, polyethylene glycol, angiotensin, and isoproterenol) before and after chronic treatment with the anticholinesterase agent, diisopropyl fluorophosphate (DFP), and its arachis oil vehicle. Only hypertonic saline and isoproterenol reliably increased water intake in both groups prior to chronic treatment. After chronic treatment hypertonic saline produced the same degree of water intake in the DFP-treated and control animals, but isoproterenol appeared to produce a greater degree of water intake in the DFP-treated than in the control rats. These results suggest that there are no gross disturbances in the mechanisms underlying intra and extracellular thirst stimuli following the development of tolerance to DFP.

Angiotensin II

Two populations of women with high and low spleen rates living in the same area of Madang, Papua New Guinea, demonstrate different immune responses to malaria.

Specific malaria and total IgM antibody responses were measured in 2 linguistically distinct coastal Papua New Guinean populations living in the same endemic malarious area, but exhibiting different adult female spleen rates (51% and 30%), in order to establish whether the higher spleen rates in the former group were due to hyper-reactive malarious splenomegaly (HMS). Malaria parasite rates were comparable, and geometric mean titres of IgG malaria antibody were the same, in both groups, indicating comparable exposure to malaria. A higher mean total IgM was observed in the high spleen (HS) rate group (6.07 g/litre, compared with 4.62 g/litre), a higher proportion was seropositive for IgM antibody to Plasmodium falciparum (63% compared with 54%), and HMS was found rather more frequently (4.7% compared with 2.6%). In both groups total IgM concentrations increased significantly with rising parity, and the mean level of 5.27 g/litre in young nulliparous women from the HS group suggested that IgM levels in this group at least were elevated from childhood. In both groups a rise in total IgM was associated with higher P. falciparum IgM geometric mean titres of antibody activity, a fall in parasite rates (HS group: 30% to 15%, P = 0.02; LS group: 24% to 0%, P = 0.034), and higher spleen rates (HS group: 38% to 65%, P = 0.001; LS group: 20% to 67%, P = 0.00012). It is concluded that the difference in spleen rates between the 2 groups was the result of differing degrees of acquired immunity to malaria, probably due to genetic differences in immune responses.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Red cell enzyme and serum protein types in the Watut Anga of Papua New Guinea.

Historically, the Angan populations of Papua New Guinea have maintained a strong isolation and absorbed limited genes from their neighbours. This lack of intermixing is reflected in their relatively homogeneous cultural, linguistic and genetic profiles. We have determined the electrophoretic variation at 26 red cell enzyme, serum protein and haemoglobin loci in the Watut Anga, a splinter group occupying the Upper Watut Valley of Morobe Province. Their genetic profile reveals the lack of a number-of variants, such as PGM2*10 and MDH*3, known to exhibit high frequencies in other highland populations. The average heterozygosity in the Watut is also much lower when compared with other Papua New Guinean populations. Their present numerical strength notwithstanding, it appears that the Angan populations have experienced population bottlenecks in their evolutionary history which may have accentuated their genetic divergence from other Papua New Guinean populations.

Adult