Squamous Cell Carcinoma of the Breast: Three Case Reports

Three cases of squamous cell carcinoma of the breast, initially diagnosed by fine needle aspiration cytology, are presented. The first case was a 49-year-old woman with a T1 tumor located in the lower outer quadrant of the left breast. Ultrasonography revealed a cystic tumor. Aspiration cytology suggested squamous cell carcinoma (SCC). Mastectomy was performed. Histological examination revealed a pure SCC. The second case was a 40-year-old woman with a T1 tumor located in the upper outer quadrant of the right breast.Ultrasonography showed a cystic tumor and aspiration cytology revealed SCC. A quad-rantectomy was performed. Histological examination revealed predominant SCC with an adeno-carcinoma component. Estrogen receptor (ER) was negative. The patient received postoperative radiation. Thirteen months after the first operation,a salvage mastectomy was performed because of local recurrence. The third case was a 61-year-old woman with a T1 tumor located in the upper outer quadrant of the right breast. Ultrasonography showed a solid tumor. Aspiration cytology revealed both SCC and adenocarcinoma. Wide excision was performed. Histological examination revealed pre-dominant SCC with foci of adenocarcinoma. ER was negative. She received postoperative radiation. The three patients are alive and disease-free 10 to 54 months after operations

Validation of the Michigan Alcoholism Screening Test--Thai version in northeast Thailand

This study was aimed to validate the Michigan Alcoholism Screening Test-Thai version (MAST-T) which was compared to the psychiatric diagnosis based on DSM-III-R criteria, as a gold standard, among the northeast population of Thailand. Sixty-one pairs of male cases with alcohol use disorders (AUD) and controls were collected through routine examination of psychiatric outpatients, 18-65 years old, who visited the Khon Kaen Psychiatric Hospital or the Northeast Drug Dependence Treatment Center which is located in Khon Kaen province, northeast Thailand between November, 1996 and February, 1997. Controls were matched for each case by sex-age (+/- 5 years)--province--urbanization. They were interviewed using the MAST-T and a structured questionnaire. Receiver operating characteristic analysis revealed that the optimum cutoff point > or = 11 on the MAST-T yields the best sensitivity and specificity (98.4% for each), along with an area under the curve of 0.998, indicating that it was sensitive and specific in discriminating AUD from non-AUD patients. This validation study of the MAST-Thai version underlines its applicability as a screening test for AUD among the northeast male Thai population.

A comparative study of chemonucleolysis with recombinant human cathepsin L and chymopapain. A radiologic, histologic, and immunohistochemical assessment

STUDY DESIGN

Investigation of the effects of recombinant human cathepsin L on intervertebral discs and comparison with the effects of chymopapain.

OBJECTIVE

To evaluate the effects of cathepsin L on intervertebral discs as an agent for chemonucleolysis.

SUMMARY BACKGROUND DATA

Cathepsin L is a typical cysteine proteinase that belongs to the papain superfamily. It plays a major role in intracellular proteolysis and is not believed to induce anaphylactic reactions.

METHODS

In vivo: Rabbit intervertebral discs were injected with recombinant human cathepsin L, its buffer solution, and chymopapain. After 1, 4, and 16 weeks the animals were killed, and radiologic and histologic examinations were performed. In vitro: The enzymatic actions of recombinant human cathepsin L and chymopapain on human intervertebral disc proteoglycans were examined immunohistochemically using antiproteoglycan antibodies.

RESULTS

In rabbit models, roentgenography showed that disc spaces treated with cathepsin L and chymopapain had become narrower 1 week after injection. Histologically, loss of safranin-O staining was observed in the anulus fibrosus of discs treated with cathepsin L. After 16 weeks, nucleus pulposus had regenerated with chondrocyte-like cells, and the safranin-O staining characteristics of the matrix also had recovered. In an immunohistochemical study, all components of the proteoglycan stained weakly after chymopapain digestion. After cathepsin L digestion, unsulfated chondroitin and core protein staining was weaker, but the chondroitin 6-sulfate staining was unaffected.

CONCLUSIONS

Cathepsin L seems to be an effective agent for chemonucleolysis. Its enzymatic action on proteoglycan appears to be different from that of chymopapain.

Decreased plasma tryptophan associated with deep white matter lesions in elderly subjects

The aim was to identify potentially treatable risk factors for cerebral white matter lesions often found on MRI in elderly persons. findings were assessed on 1.0 T MRI of 178 subjects living in the community and aged 60 years or older. Participants underwent standardised evaluations including standard questionnaires, a physical and neurological examination, cognitive function tests, electrocardiogram, a complete blood chemistry panel, and plasma amino acid measurements. Brain MRI infarcts, deep white matter lesions (DWMLs), and periventricular hyperintensities were found in 26%, 43%, and 29% of the 178 participants, respectively. Subjects with DWMLs were significantly older and had a higher frequency of hypertension, higher systolic blood pressure, and more brain infarcts, but lower plasma concentrations of tryptophan. In the multivariate model, greater age and lower plasma tryptophan concentrations were independently associated with DWMLs. Tryptophan concentrations were inversely related to DWML grading, whereas hypertension and brain infarction were more common in subjects with higher extents of DWMLs. The present study suggests that greater age and lower plasma tryptophan concentrations were important in producing DWMLs in elderly subjects.

Leukemia inhibitory factor, a potent cardiac hypertrophic cytokine, enhances L-type Ca2+ current and [Ca2+]i transient in cardiomyocytes

This study investigates whether leukemia inhibitory factor (LIF), a potent cardiac hypertrophic cytokine, affects the L-type Ca2+ current (I(Ca,L)) and intracellular Ca2+ concentrations ([Ca2+]i) in cardiomyocytes. I(Ca,L) was recorded using a whole cell patch clamp configuration in guinea pig cardiomyocytes, and the [Ca2+]i transient was detected by use of Fluo-3 in rat cardiomyocytes. Cells were preincubated with LIF (1000 U/ml) for 15 min before whole cell recording. LIF increased I(Ca,L) by 41.8%. LIF synergistically increased I(Ca,L) with isoproterenol. Preincubation with H89 did not inhibit the LIF-induced increase in I(Ca,L), indicating that this phenomenon is PKA-independent. PD98059 completely inhibited the increase in I(Ca,L), and this effect was dose-dependent (IC50=3.6 micromol/l). Other signal transduction inhibitors including AG490, SB203580, chelerythrine, genistein, and KN62 did not affect the LIF-induced increase in I(Ca,L). Perforated patch clamp recording revealed that LIF maximally increased the I(Ca,L) by 25% at 15 min. LIF also increased the peak [Ca2+]i transient level by 63% at 15 min. PD98059 fully inhibited the increase in the [Ca2+]i transient. In conclusion, LIF increased I(Ca,L) and the [Ca2+]i transient in cardiomyocytes, and the Raf-1/MEK/ERK pathway might be involved in the modulation of this activation.

Adrenomedullin promotes epithelial restitution of rat and human gastric mucosa in vitro

We have investigated the effect of adrenomedullin (AM) on restitution of mucosal integrity following damage in rat and human gastric mucosa, measuring the potential difference (PD) on a mucosal strip mounted on an Ussing chamber. Mucosal damage was induced by 0.5, 1.0, and 2.0 M NaCl solution, and it caused an immediate and significant decrease in PD. In the rat AM group, PD recovered significantly more than in control group at 120 min after exposure to 0.5 M (p < 0.01) and 1.0 M (p < 0.05) NaCl solution. In the human AM group, PD completely recovered at 120 min after exposure to 0.5 M (p < 0.05) NaCl solution. In rat mucosa damaged by 0.5 M NaCl solution, the effect was inhibited by human (h)-CGRP(8-37) and there was no significant difference between the h-CGRP(8-37) group and control group. On immunohistochemical examination of rat gastric mucosa, AM was detected within the chief cell. AM probably promotes epithelial restitution primarily through the CGRP receptor, but it does not ameliorate more severe damage of gastric mucosa in vitro.

Hexavalent chromium responsible for lung lesions induced by intratracheal instillation of chromium fumes in rats

Lung toxicity of chromium fumes (Cr fumes) was examined by a single intratracheal instillation into rats of 10.6 mg and 21.3 mg Cr fumes/kg body weight and by repeated (3 times) instillations of 10.8 mg and 21.7 mg Cr fumes/kg. The pathological changes were compared with those induced by single administrations of 3.2 mg and 19.2 mg Na2CO3 solution-insoluble fraction of Cr fumes (Cr-Fr)/kg and 20.8 mg commercially available chromium (III) oxide powder (Cr (III) oxide)/kg. Single and repeated administrations of Cr fumes suppressed growth rate in a dose-dependent manner, but administrations of Cr-Fr and Cr (III) oxide did not. A single administration of Cr fumes produced granulomas in the entire airways and alveoli with progressive fibrotic changes, as well as severe mobilization and destruction of macrophages and foamy cells. Those histopathological changes were aggravated by the repeated administration of Cr fumes. On the other hand, single administrations of Cr-Fr and Cr (III) oxide produced no remarkable histopathological changes. Cr fumes were found to be composed of 73.5% chromium (III) oxide and 26.5% chromium (VI) oxide. The primary particles of Cr fumes and Cr-Fr were similar, 0.02 micron in size (sigma g: 1.25), and Cr (III) oxide particles were 0.30 micron in size (sigma g: 1.53), measured by analytical electron microscopy (ATEM). Diffuse clusters of the primary particles in Cr fumes were identified as Cr (VI) oxide. The present results suggested that the lung toxicity of Cr fumes was mainly caused by these Cr (VI) oxide (CrO3) particles in Cr fumes.

The economic impact of pandemic influenza in the United States: priorities for intervention

We estimated the possible effects of the next influenza pandemic in the United States and analyzed the economic impact of vaccine-based interventions. Using death rates, hospitalization data, and outpatient visits, we estimated 89,000 to 207,000 deaths; 314,000 to 734,000 hospitalizations; 18 to 42 million outpatient visits; and 20 to 47 million additional illnesses. Patients at high risk (15% of the population) would account for approximately 84% of all deaths. The estimated economic impact would be US$71.3 to $166.5 billion, excluding disruptions to commerce and society. At $21 per vaccinee, we project a net savings to society if persons in all age groups are vaccinated. At $62 per vaccinee and at gross attack rates of 25%, we project net losses if persons not at high risk for complications are vaccinated. Vaccinating 60% of the population would generate the highest economic returns but may not be possible within the time required for vaccine effectiveness, especially if two doses of vaccine are required.

[A case of noninflammatory corneal edema following anterior-posterior radial keratotomy successfully treated by topical steroids]

BACKGROUND

Corticosteroids seems to affect the functions of corneal endothelial cells directly in addition to its anti-inflammatory effect.

CASE

A 69-year-old male presented with left blurred vision and decreased visual acuity in both eyes. He had undergone anterior-posterior radial keratotomy for myopia in both eyes 40 years before. Both eyes showed mild corneal stromal edema in the pupil area. We diagnosed the condition as corneal edema secondary to cell loss and dysfunction of corneal endothelium after surgery. The stromal edema further advanced in the left eye one month later. The corneal thickness increased from the initial value of 619 to 631 microns. The corrected visual acuity decreased from 0.5 to 0.06. There were no signs suggesting inflammatory reaction. The left eye was then treated with topical corticosteroids as eye-drops and by subconjunctival injection. The corneal thickness decreased to 546 microns two months later with improvement of visual acuity to 0.5.

CONCLUSION

This case illustrates that topical corticosteroids may be effective for corneal edema through their anti-inflammatory effect and possible activation of the endothelium.

Anovulations in an ovary during two menstrual cycles enhance the pregnancy potential of oocytes matured in that ovary during the following third cycle

The aim of this study was to test whether ovulation from an ovary affects the health of oocytes from dominant follicles in that ovary two cycles later. A total of 80 women each with two intact ovaries underwent 270 treatment cycles (155 natural cycles and 115 clomiphene citrate cycles) all showing unilateral ovulation. The results from the in-vitro fertilization (IVF) treatment were grouped according to whether ovulation (O) or anovulation (A) (no ovulation) was observed in the ovary with dominant follicle during the treatment cycle in the previous two cycles: O-O, A-O, O-A and A-A (previous second cycle-previous first cycle). The rate of pre-embryo formation in A-A was significantly higher than that of O-A. The pregnancy rate in A-A (29%) was also higher than those of O-A (13%), A-O (9%) and O-O (5%). These rates increased from O-O to A-A as the number of previous ovulations in an ovary decreased. The presence of a corpus luteum and/or a dominant follicle is likely to exert local negative effects on the health of the oocyte contained in the follicle selected to ovulate up to two cycles later. Anovulations in an ovary for two menstrual cycles may therefore provide improved conditions for the development of a healthier oocyte with an increased pregnancy potential.

Synovial sarcoma in the parapharyngeal space: case report and review of the literature

We encountered a rare case of synovial sarcoma in the parapharynx of a 47-year-old Japanese man. This patient presented with an enlarging tumor in the right side of his neck that had grown progressively over a 4-week period. Radiological examinations revealed that the tumor arose from the parapharyngeal space. The tumor could not be completely removed at surgery. Metastasis to the lumbar vertebra was detected postoperatively. The patient underwent three courses of chemotherapy and the delivery of palliative radiation to the lumbar vertebra without success. The patient died of lung metastasis 7 months after surgery.

Differential distribution of subchains of the basement membrane components type IV collagen and laminin among the amniotic membrane, cornea, and conjunctiva

PURPOSE

Amniotic membrane transplantation has been reported to be an effective surgical procedure for the reconstruction of the anterior segment of the eye. To understand better the function of transplanted amniotic membrane, we compared the distributions of subchains of type IV collagen and laminin in the amniotic membrane to those in the cornea and conjunctiva.

METHODS

Five human corneas with conjunctivas and three human amniotic membranes were frozen in OCT compound. Cryosections were cut with a cryostat and stained by an indirect immunofluorescent microscopy. We used antibodies of the collagen alpha2(IV) and alpha5(IV) subchains, laminin-1, laminin-5, fibronectin, and type VII collagen.

RESULTS

In the conjunctival basement membrane and the amniotic membrane, fluorescence was evident for collagen alpha2(IV) but not for collagen alpha5(IV). By contrast, in the corneal basement membrane, fluorescence was apparent for the collagen alpha5(IV) subchain but not for the collagen alpha2(IV) subchain. Laminin-1, laminin-5, fibronectin, and type VII collagen were present in all the basement membranes examined.

CONCLUSION

The distribution of alpha subchains of type IV collagen in the amniotic membrane was identical to that in the conjunctiva but different from that in the cornea. No difference in the distribution pattern of other basement membrane components was observed. These results demonstrate that the basement membrane of the amniotic membrane and the conjunctiva might share the same components; therefore, the amniotic membrane might be useful as a replacement for the basement membrane of the conjunctiva.

Middle-term results of anatomic medullary locking total hip arthroplasty

We report the results of cementless, anatomic, medullary locking hip prosthesis application in our first consecutive series. We used the so-called Asian size of prosthesis with proportionally smaller stem sizes in both diameter and length. Forty-seven stems and sockets were analyzed with a mean follow-up of 69 months. The mean Merle d'Aubigné hip scores were 8 points preoperatively and 16 points at the final follow-up. Radiologically, the stems showed excellent stability without loosening. Stress shielding around the stems did occur in most cases but did not progress. Preoperative bone quality influenced the extent of stress shielding evaluated at the final follow-up: higher stress shielding was noted in poorer quality bones at the time of operation. There were problems with the sockets. The shallow socket and impingement at the protruded rim seemed to cause a high incidence of dislocation (13%). Massive polyethylene wear occurred in 5 sockets. These sockets were 48 and 46 mm in diameter with 26 mm heads. In conclusion, the stems of the anatomic medullary locking hip prostheses used in Japan showed satisfactory stability even in poor quality bones, but there were problems with the polyethylene liners. Our solution was to use larger sockets with 22 mm heads.

Detection and sequence analysis of borna disease virus p24 RNA from peripheral blood mononuclear cells of patients with mood disorders or schizophrenia and of blood donors

Borna disease virus (BDV) p24 RNA was detected in the peripheral blood mononuclear cells (PBMCs) of psychiatric patients and blood donors by nested reverse transcriptase PCR (RT-PCR). The prevalences of BDV p24 RNA in patients with mood disorders (4%) and schizophrenia (4%) were not significantly different from that in blood donors (2%). This finding was inconsistent with previous reports that showed either a high prevalence or absence of BDV p24 RNA in patients with psychiatric disorders. The differences in BDV p24 RNA prevalence in these studies may be due to differences in the criteria for positivity, the number of PBMCs used for RNA extraction, or the amount of RNA tested for nested RT-PCR or to laboratory contamination. Sequence analysis of BDV p24 RNA from the PBMCs of patients and blood donors showed a high nucleotide sequence conservation but definite nucleotide mutations compared with horse BDV p24 RNA sequences. In comparison with human BDV p24 RNA sequences previously reported from Japan and Germany, there were several positions with silent nucleotide mutations among these clones.

Monolayer Behavior of Tetraphenylporphyrin Derivatives Containing Four Fluorocarbon Chains and Optical Properties of Their Monolayer Assemblies

For tetraphenylporphyrin derivatives substituted with four fluorocarbon chains (TFPP), monolayers on the water surface were studied with the Brewster angle microscope together with pressure-area curves. It was found that heterogeneous aggregated structures of the monolayers were dependent upon the chain length of fluorocarbons, the metal-free or Mn-TFPP, and the periods after spreading. Polarized UV-visible spectra for the monolayer assemblies indicated that the porphyrin rings in the films were tilted on the average, but had a tendency to adopt an orientation more parallel to the water surface as the chain length of the fluorocarbon increased. The third-order nonlinear optical susceptibility for the monolayer assembly of TFPP with the shorter chains was found to be 7.0 x 10(-13) esu, and those of Mn-TFPP were enlarged. Copyright 1998 Academic Press.

Effects of okadaic acid on rat colon

Effects of okadaic acid (OA) on mucosal damage were examined in rat colon. OA was sprinkled on rat colon mucosa under observation with an electronic-endoscopic system, and OA was also applied to the in vivo microscopic field. The OA-induced changes in transepithelial conductance (Gt) were measured by the Ussing voltage clamp technique. By endoscopic observation, the luminal sprinkling of OA (60 nmol/kg) evoked transient microthrombi in the submucosal venule, which was followed by mucosal edema. Histological study after endoscopic observation showed submucosal fluid retention, suggesting an increase of vascular permeability. The microthrombi were also detected by in vivo microscopy. By electrophysiological study after endoscopic observation with and without OA addition, the basal Gt values were 54+/-6.2 and 36.2+/-4.2 mS/cm2, respectively (P < 0.01). Furthermore in control rats, the serosal addition of OA evoked an increase in Gt in a concentration-dependent manner without increasing lactate dehydrogenase release. 2,4,6-Triaminopyrimidinium inhibited OA-induced Gt change by 60%. These results indicate that OA evokes an increase in paracellular permeability of epithelium. We conclude that the developed microthrombi are the first key event of OA-induced mucosal damage, followed by an increase in permeability in the submucosal venule and in the paracellular pathway of the epithelium.

Activation of phospholipase A2 by the nociceptin receptor expressed in Chinese hamster ovary cells

To gain insight into the molecular mechanism for nociceptin function, functional coupling of the nociceptin receptor expressed in Chinese hamster ovary (CHO) cells with phospholipase A2 (PLA2) was examined. In the presence of A23187, a calcium ionophore, activation of the nociceptin receptor induced time- and dose-dependent release of arachidonate, which was abolished by pretreatment of the cells with pertussis toxin (PTX). Immunoblot analysis using anti-Ca2+-dependent cytosolic PLA2 (cPLA2) monoclonal antibody demonstrates that activation of the nociceptin receptor induces a time- and dose-dependent electrophoretic mobility shift of cPLA2, suggesting that phosphorylation of cPLA2 is induced by the nociceptin receptor. Pretreatment of the cells with PD98059, a specific mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1 inhibitor, or staurosporine, a potent inhibitor of serine/threonine protein kinases and tyrosine protein kinases, partially inhibited the nociceptin-induced cPLA2 phosphorylation and arachidonate release. These results indicate that the nociceptin receptor expressed in CHO cells couples with cPLA2 through the action of PTX-sensitive G proteins and suggest that cPLA2 is activated by phosphorylation induced by the nociceptin receptor via mechanisms partially dependent on p44 and p42 mitogen-activated protein kinases.

Suppressive effects of nimesulide, a selective inhibitor of cyclooxygenase-2, on azoxymethane-induced colon carcinogenesis in mice

The effects of nimesulide, a selective inhibitor of cyclooxygenase-2 (COX-2) on azoxymethane (AOM)-induced colon carcinogenesis were investigated in mice. AOM at a dose of 10 mg/kg body wt was administered to male ICR mice once a week for 6 weeks. The animals were fed on AIN-76A powder diet containing nimesulide at doses of 200 or 400 p.p.m., starting the day before the first carcinogen treatment until the end of the experiment, at week 30. Administration of nimesulide reduced the incidence of colon carcinomas to 32 and 25% for the AOM + 200 and 400 p.p.m. nimesulide groups, respectively, compared with the AOM + basal diet group (50%). Multiplicities of colon carcinomas in the 200 and 400 p.p.m. nimesulide-treated groups were 0.70 +/- 0.28 and 0.35 +/- 0.11, respectively, being significantly smaller than the AOM alone value (1.79 +/- 0.47). The sizes of the colon carcinomas in the nimesulide-treated groups were also decreased. No significant influence on liver and lung tumor development was apparent. Thus, nimesulide exerted a suppressive effect on AOM-induced colon carcinogenesis in mice.

[Cerebellar infarction due to vertebral artery dissection in a girl]

We report here a case of vertebral artery dissection, which is rare in childhood. A 12-year-old, previous healthy girl was admitted to our hospital with symptoms of vertigo, tinnitus, hearing loss, nausea and vomiting. Although there was neither higher cortical dysfunction, motor weakness, sensory disturbance nor slurred speech. She could not stand up because of severe vertigo. Cranial magnetic resonance imaging (MRI) revealed a subacute cerebellar infarct. A left vertebral artery angiogram on the hospital day 3 demonstrated a sharp narrowing at the C1-C2 level. After an anticoagulant therapy for about 2 weeks, all the symptoms disappeared except for mild tinnitus. Two months later, a left vertebral artery angiogram showed an abrupt occlusion at the C1 level. MRI T1-weighted images demonstrated a thrombus within the false lumen of the dissected vessels. A flow void revealed the patency of the residual true lumen. From these findings, we made a diagnosis of vertebral artery dissection, which was considered to have caused cerebellar infarction. The patient was mostly normal at discharge, and 100 mg/day of aspirin has been given until present.

Concurrent generation of nitric oxide and superoxide inhibits proteoglycan synthesis in bovine articular chondrocytes: involvement of peroxynitrite

OBJECTIVE

Nitric oxide (NO), widely assumed to be a mediator of interleukin 1 (IL-1), inhibits proteoglycan synthesis in articular chondrocytes. IL-1 also produces superoxide anion. We hypothesized that the IL-1 inhibited proteoglycan synthesis is the result of peroxynitrite formed by the reaction of NO with superoxide.

METHODS

Bovine articular chondrocytes were cultured in the presence of SIN-1, which leads to simultaneous generation of both NO and superoxide. Proteoglycan synthesis was measured based on the incorporation of [35S] sulfate, and the presence of peroxynitrite was confirmed using immunohistochemistry.

RESULTS

SIN-1 inhibited proteoglycan synthesis and superoxide dismutase reversed SIN-1 inhibited proteoglycan synthesis, indicating the simultaneous generation of superoxide is essential to inhibit proteoglycan synthesis. IL-1 induced peroxynitrite in articular chondrocytes and addition of peroxynitrite inhibited proteoglycan synthesis.

CONCLUSION

The concurrent generation of superoxide anion and NO is required for the action of IL-1 to inhibit proteoglycan synthesis. Peroxynitrite is a candidate for this underlying mechanism.

A novel three-dimensional crystal of bacteriorhodopsin obtained by successive fusion of the vesicular assemblies

When the two-dimensional crystal of bacteriorhodopsin (bR), purple membrane, is incubated at high temperature (32 degreesC) with a small amount of the neutral detergent octylthioglucoside in the presence of the precipitant ammonium sulfate, a large fraction of the membrane fragments is converted into spherical vesicles with a diameter of 50 nm, which are able to assemble into optically isotropic hexagonal crystals when the precipitant concentration is increased. The vesicularization of purple membrane takes place under such a condition that the miscibility of the detergent to the aqueous phase becomes very low, and we suggest that it is initiated by insertion of the detergent molecules into the membrane. At low temperature, the transformation into the vesicular structure is inhibited and no large crystal is produced directly from membrane/detergent/precipitant mixtures. When a suspension of the spherical vesicles produced at the high temperature is cooled and concentrated below 15 degreesC, however, a birefringent hexagonal crystal is produced that diffracts X-rays beyond 2.5 A resolution. This new crystal belongs to the space group P622 with unit cell dimensions of a=b=104.7 A and c=114.1 A, and it is shown to be made up of stacked planar membranes, in each of which the bR trimers are arranged on a honeycomb lattice and the space among the proteins is filled with the detergent molecules and native lipids. These stacked membranes are suggested to be produced by successive fusion of the spherical vesicles. This implies that the crystallization is achieved without any step for complete solubilization of the protein. The present result offers a unique crystallization method that may be applicable to such membrane proteins that are liable to denature in the presence of an excess amount of detergent.

Morphology and function of human benign tumors and normal thyroid tissues maintained in severe combined immunodeficient mice

In the improved SCID (severe combined immunodeficient) mice, various human benign tumors of the head and neck region were well maintained morphologically and functionally for 3 years until the experiments were terminated, e.g. transplanted parathyroid adenoma secreted parathyroid hormone (PTH) in the SCID mice for more than 1 year. Normal human thyroid tissue was also well maintained in the SCID mice for 3 years. Rapid and high uptake of radioiodine into the transplanted human thyroid tissue was observed. Furthermore, transplanted human thyroid tissue secreted thyroid hormone (T3) and T3 secretion was stimulated by the injection of human thyroid stimulating hormone (TSH). These findings suggest that the improved SCID mice will provide an invaluable experimental system for investigating the function of normal human tissues and the influence of endogenous and exogenous factors on human tissues.