Hidradenitis suppurativa: a disease of follicular epithelium, rather than apocrine glands

A retrospective study was made of the histopathology of axillary skin excised from 12 patients with hidradenitis suppurativa. In the majority of cases (10 out of 12), squamous epithelium-lined structures, in the form of cysts or sinuses were identified in the dermis. Laminated keratin was present in all these structures and half of the cysts also contained hair shafts, suggesting that they are derived from hair follicles. Only a small proportion of cases (4 out of 12) displayed inflammation in apocrine glands, and in these the inflammation was also seen around eccrine glands, hair follicles and the epithelium-lined structures. However, in cases where the epithelium of the 'cysts' was disrupted, the inflammatory infiltrate appeared to be centred around these areas. These observations suggest that the squamous epithelium-lined structures, which probably represent abnormal dilated hair follicles, are a more constant diagnostic feature in hidradenitis suppurativa than inflammation of apocrine glands which appears to be a secondary phenomenon.

New brain perfusion imaging agents based on 99mTc-bis(aminoethanethiol) complexes: stereoisomers and biodistribution

In developing new brain perfusion imaging agents, we prepared 99mTc complexes of racemic mixtures of bis(aminoethanethiol) (BAT) derivatives containing an N'-benzylpiperazinyl (BPA) side chain. Due to the presence of a chiral center, a mixture of diastereomers (syn and anti) following chelation with the 99mTc (no-carrier-added) was obtained. The neutral and lipid-soluble 99mTc-BPA-BAT (99mTc, T1/2 = 6 h) isomers were separated. The syn and anti isomers of carrier-added 99Tc-BPA-BAT (99Tc, T1/2 = 2 x 10(5) years) were also synthesized, separated, and crystallized. The X-ray crystallography of 99Tc-BPA-BAT showed the syn and anti conformations (in relationship with the central TC(=O)N2S2 core). Despite a similarity in the partition coefficients for the two isomers, the syn isomer showed a higher in vivo brain uptake and longer brain retention in rats (2.77 and 1.08% dose/organ at 2 and 15 min) than that of the corresponding anti isomer (0.57 and 0.27% dose/organ at 2 and 15 min). This information is important and should be taken into consideration when new 99mTc-labeled brain perfusion imaging agents are being designed.

Synthesis, characterization and biodistribution of neutral and lipid-soluble 99mTc-PAT-HM and 99mTc-TMR for brain imaging

Two new ligand systems for complexation with 99mTc were prepared. The two analogs of bisaminoethanethiol (BAT): N,N'-bis(2-methyl-2-mercaptopropyl)-2,2-dimethylpropylenediamin e (PAT-HM) and N,N'-bis[2-(2-ethyl-1-mercaptopropyl)] ethylenediamine (TMR), form neutral and lipid soluble complexes with 99mTc that readily penetrate the blood-brain barrier following i.v. injection into rats. Although the 99mTc chelates do not display the prolonged brain retention required for use in single photon emission computed tomographic imaging studies, the fact that each ligand forms a neutral and lipid-soluble complex of high chemical stability when coordinated with 99mTc warrants further investigation to increase the site- and organ-specificity of these agents.

Synthesis of new bis(aminoethanethiol) (BAT) derivatives: possible ligands for 99mTc brain imaging agents

In developing new brain perfusion imaging agents for single photon emission computed tomography (SPECT), five 99mTc-labeled neutral bis(aminoethanethiol) (BAT) derivatives capable of crossing the blood-brain barrier are reported. The five ligands are prepared by two versatile synthetic methods that can specifically introduce substituents on one of the carbons between two nitrogens. These ligands formed stable and neutral complexes with the reduced 99mTc, using either Sn(II) or sodium borohydride to reduce sodium [99mTc]pertechnetate. The biodistribution in rats was evaluated with [125I]iodoantipyrine, a freely diffusible tracer, as the internal reference. Compounds with a free hydroxyl group, 6 and 15, showed lower brain uptake. High initial brain uptake was observed for compounds 10 and 14, 1.28 and 2.30% dose/organ, respectively. Compounds of this type may be used as a basis for future structural modification to improve brain uptake and retention.

Metabolism and disposition of diphacinone in rats and mice

14C-diphacinone (0.2-1.5 mg/kg) was orally administered to rats and mice. Residue distribution in various tissues and radiocarbon elimination in feces and urine were determined. More than 60% of the administered radiocarbon was eliminated in feces and about 10% in urine in 4 days from mice and in 8 days from rats. The greatest amount of radioactivity in tissues of both rats and mice appeared in liver. Brain, muscle, blood, and fat had the lowest residue levels. Metabolites in feces and liver were chromatographically isolated and identified by mass spectrometry. In addition to unchanged diphacinone, four hydroxylated metabolites were identified in feces and liver. Hydroxylation occurred on either or both the indandione or phenyl rings. The positions of the hydroxy groups on the rings were not established.

N-Acetyl-beta-glucosaminidase activity in hydatidiform mole

The N-acetyl-beta-glucosaminidase activity in hydatidiform mole is two-fold higher than that in full-term placenta. Qualitatively, the enzymes from the two tissues are similar with respect to KM values and pH optima. Both enzymes also contain a new isoenzyme form detectable by polyacrylamide gel electrophoresis. However, the molar enzyme is more susceptible to heat denaturation, presumably due to the presence of a higher level of the heat-labile isoenzyme form A in this tissue. Data are also presented incicating that the placenta is not the source of the N-acetyl-beta-glucosaminidase activity in maternal serum.

beta-Glucuronidase and oestrogens in hydatidiform mole

The activity of beta-glucuronidase (beta-D-glucuronide glycuronohydrolase, EC 3.2.1.31) in placental and hydatidiform mole tissue and in sera from non-pregnant, normal and molar pregnant women was determined. The oestrogen concentrations in the two solid tissues were also assayed. Significant differences were found in the activities of the enzyme between placental and molar tissues and among the various sera. The lower activity in molar serum corresponds to a lower concentration of oestrogens in molar tissues and may be regarded as a response to the alleviation of conjugation requirements.