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Biomedical subjects

M Potts

Publications and source records attributed to M Potts.

At least 91 records · Page 5Linked to original sources

Should oral contraceptives be available without prescription?

In this paper, it is argued that oral contraceptives should be available without prescription. Prescription status entails heavy costs, including the dollar, time, and psychological costs of visiting a physician to obtain a prescription, the financial and human costs of unintended pregnancies that result from the obstacle to access caused by medicalization of oral contraceptives, and administrative costs to the health care system. After a review and evaluation of the reasons for strict medical control of oral contraceptives in the United States, safety concerns anticipated in response to the proposal discussed here are addressed. Also, concerns that prescription status is necessary for efficacious use are evaluated. It is concluded that neither safety nor efficacy considerations justify prescription status for oral contraceptives. Revised package design and patient labeling could allow women to screen themselves for contraindications, to educate themselves about danger signs, and to use oral contraceptives safely and successfully. Several alternatives to providing oral contraceptives by prescription with current package design and labeling and selling them over the counter are suggested; the proposals discussed would make these safe and effective contraceptives easier to obtain and to use.

Contraceptives, Oral↗

Myoglobin in a cyanobacterium.

Myoglobin was found in the nitrogen-fixing cyanobacterium Nostoc commune. This cyanobacterial myoglobin, referred to as cyanoglobin, was shown to be a soluble hemoprotein of 12.5 kilodaltons with an amino acid sequence that is related to that of myoglobins from two lower eukaryotes, the ciliated protozoa Paramecium caudatum and Tetrahymena pyriformis. Cyanoglobin is encoded by the glbN gene, which is positioned between nifU and nifH-two genes essential for nitrogen fixation-in the genome of Nostoc. Cyanoglobin was detected in Nostoc cells only when they were starved for nitrogen and incubated microaerobically.

Amino Acid Sequence↗

AIDS in Africa.

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Acquired Immunodeficiency Syndrome↗

Gene cluster rpoBC1C2 in cyanobacteria does not constitute an operon.

The core enzyme of the cyanobacterial DNA-dependent RNA polymerase contains a unique component, gamma, which is absent from the corresponding enzymes of other eubacteria. In the heterocystous cyanobacterium Nostoc commune the gene encoding gamma, rpoC1, is immediately adjacent to, and downstream of, rpoB. The rpoC1 gene, and a 3' adjacent gene, rpoC2, correspond to the single rpoC gene found in Escherichia coli with respect to those domains conserved within their translational products. Northern analysis and primer extension assay show that in N. commune, rpoC1 and rpoC2 are transcribed separately from rpoB. The promoter of rpoC1C2 can direct the expression of a promotorless lacZ gene in E. coli. As a consequence, cyanobacterial rpo gene expression is distinct from the mode of cotranscription described for the equivalent sequences found in other eubacteria, archaebacteria, and plant chloroplasts. Also in this paper, a simple protocol for RNA isolation, which should be applicable for RNA isolation from plant cells, is presented.

Base Sequence↗

Paraguayan pharmacies and the sale of pseudo-abortifacients.

This study was conducted in 1985 in Asunción, Paraguay, 6 years after the closure of the state supported family planning services. Data from national surveys in 1977 and 1987 permit a comparison of sources of contraceptive supplies before and after the elimination of government support for family planning. The purchase of pseudo-abortifacients from private pharmacies was used as an indication of induced abortion. After the loss of government clinics, it is suggested that some women turned to pharmacists to obtain pseudo-abortifacients when faced with unwanted pregnancy. There is an indication of increased pseudo-abortifacient use, particularly among unmarried women and those from poorer neighbourhoods.

Abortifacient Agents↗

Do the benefits of breastfeeding outweigh the risk of postnatal transmission of HIV via breastmilk?

Conflicting recommendations have been offered about whether HIV+ mothers should breastfeed. Since there is a strong precedent for US infant feeding practices to be imitated in developing countries, a model was constructed to estimate infant mortality if the CDC admonition for HIV+ mothers not to breastfeed were upheld in less developed settings. Estimates are given for infant mortality in the presence and absence of breastfeeding across several baseline levels of infant mortality and across several theoretical rates of transmission through breastfeeding. The infant mortality associated with HIV infection acquired through breastfeeding is estimated to be lower than the mortality associated with the diseases of infancy that would result if breastmilk were withheld. The difference in these estimates is greater in areas with high baseline levels of infant mortality.

Acquired Immunodeficiency Syndrome↗

Novel water stress protein from a desiccation-tolerant cyanobacterium. Purification and partial characterization.

A desiccation-tolerant cyanobacterium Nostoc commune accumulates a novel group of acidic proteins when colonies are subjected to repeated cycles of drying and rehydration. The proteins occur in high concentrations; they have isoelectric points between 4.3 and 4.8 and apparent molecular masses between 30 and 39 kDa. The purification of three of these proteins with molecular masses of 33, 37, and 39 kDa is described. The amino-terminal sequence of the 39-kDa protein is Ala-Leu-Tyr-Gly-Tyr-Thr-Ile-Gly-Glu. Peptide mapping of the 39- and the 33-kDa proteins, using different protease, gave similar patterns of digestion fragments. The amino acid compositions of the proteins isolated were similar, and each cross-reacted with a polyclonal antibody raised against the largest (39-kDa) protein. The results indicate that the microheterogeneity observed was generated by in vivo proteolysis of the 39-kDa protein. It is suggested that this protein is a water stress protein with a protective function on a structural level.

Amino Acid Sequence↗

Performance of the copper T-380A intrauterine device in breastfeeding women.

The effect of breastfeeding on performance of the TCu-380A IUD was evaluated using data derived from multicenter clinical trials. Insertion events for breastfeeding women (N = 559) and non-breastfeeding women (N = 590) were compared as well as discontinuations of IUD use through six months following insertion. Results indicate that breastfeeding women inserted with a TCu-380A are more likely than non-breastfeeding women to have a smooth, pain-free insertion, few postinsertion bleeding and pain problems, and a high rate of continuation of IUD use. There were no uterine perforations reported from either group of women.

Adult↗