Clinical factors associated with the symptoms of constipation in patients with diabetes mellitus: A multicenter study

BACKGROUND AND AIM

Changes in treatment protocols for patients with diabetes mellitus (DM) may influence the functions of the digestive tract. This study examined possible clinical factors associated with the symptoms of constipation in patients with DM.

METHODS

This was a multicenter study. Participants were consecutive Japanese patients undergoing treatment for type 1 or type 2 DM. Constipation was evaluated using the gastrointestinal symptom rating scale. Diabetic neuropathy was evaluated by the presence or absence of peripheral neuropathy of the lower limbs.

RESULTS

Of 419 participants, 258 were men and 161 women (ratio: 1.6:1), with a mean age of 63.6 ± 12.5 years. In multivariate analysis, symptoms of constipation were significantly associated with age (odds ratio [OR] = 1.02, 95% confidence interval [CI]: 1.01-1.04, P = 0.032), lower mental component summary (OR = 3.31, 95% CI: 1.69-6.48, P < 0.001), diabetic retinopathy (OR = 1.99, 95% CI: 1.14-3.45, P = 0.015), and diabetic neuropathy (OR = 1.86, 95% CI: 1.10-3.16, P = 0.021). In patients with peripheral neuropathy of the lower limbs, regardless of the presence of other complications (diabetic nephropathy and diabetic retinopathy), the prevalence of symptoms of constipation was twice that of patients without peripheral neuropathy (40.0-49.1% vs 22.0%). Diabetic drugs were not associated with symptoms of constipation.

CONCLUSIONS

Diabetic neuropathy, defined as peripheral neuropathy of the lower limbs, was significantly associated with symptoms of constipation. Peripheral neuropathy of the lower limbs is not a direct risk factor for constipation but may be a useful criterion when assessing whether constipation is associated with DM.

Pathological correlations between podocyte injuries and renal functions in canine and feline chronic kidney diseases

Podocytes cover the glomerulus and their adjacent foot processes form a principal barrier called the slit diaphragm. Podocyte dysfunctions, including podocyte loss and slit diaphragm disruptions, induce chronic kidney diseases (CKD). In this study, we analyzed the correlations between podocyte injuries and renal dysfunctions in domestic carnivores. Dogs and cats were divided into normal and CKD groups according to renal histopathology and plasma creatinine values. Immunostaining results showed that linear reactions of slit diaphragm molecules, e.g., nephrin, podocin, and ACTN4, were parallel to glomerular capillaries in all animals. However, in dogs, reactions of nephrin and ACTN4 were changed to a granular pattern in the CKD group, and their intensities significantly decreased with the number of podocytes in the glomerulus. Moreover, the expression of nephrin and ACTN4 negatively correlated with creatinine. Real-time PCR analysis showed that nephrin mRNA expression in the kidneys of CKD dogs was significantly lower than that in normal animals, and negatively correlated with creatinine. Although no significant correlation between renal dysfunction and podocyte injury was detected in cats, histoplanimetric scores of tubulointerstitial lesions in CKD cats were higher than those in both normal cats and diseased dogs. Furthermore, mRNAs of WT1 and SD molecules were detected in urine from CKD animals. In conclusion, podocyte injuries such as podocytopenia and decreased expression of nephrin and ACTN4 in the glomerulus were more strongly correlated with renal dysfunction in dogs than in cats. These findings suggest that the CKD pathogenesis, especially susceptibilities to podocyte injuries, differed between dogs and cats.

[Mediastinal neurilemmoma originating in the right phrenic nerve: a case report]

We report on a 31-year-old man with a mediastinal neurilemmoma originating in the right phrenic nerve. The patient was admitted because of abnormal chest X-ray shadows observed during a routine checkup. A preoperative diagnosis of bronchial cyst in the mediastinum was made. The tumor was resected by video-assisted thoracic surgery. It was 3 x 4 x 3 cm in size, weighted 15 g, and originated in the right phrenic nerve. The histopathologic diagnosis was mediastinal neurilemmoma. Only 14 cases have been reported in the Japanese literature.

Gene transduction for disseminated intraperitoneal tumor using cationic liposomes containing non-histone chromatin proteins: cationic liposomal gene therapy of carcinomatosa

Cationic liposome-mediated gene therapy of cancer has been examined in a disseminated intraperitoneal tumor model. A combination of the strong CAG promoter-enhancer unit and high mobility group 1,2 (HMG-1,2) proteins has been used to improve transfection efficiency. The optimal deoxyribonucleic acid (DNA) and HMG-1,2 concentration ratio was determined in in vitro studies. Subsequently, we administered the liposome-DNA-HMG-1,2 complex intraperitoneally to tumor bearing nude mice and defined the most efficient concentration of liposomes. Using this approach, the median survival of tumor bearing nude mice was prolonged by the administration of a human tumor necrosis factor-alpha (TNF-alpha) gene inserted into a eukaryotic strong expression vector (pcagTNF-alpha) and exogenously added interferon-gamma (INF-gamma) (72 +/- 3 days: mean +/- s.e.). By contrast, survival was 36 +/- 3, 39 +/- 3 and 46 +/- 4 days in group receiving the TNF-alpha gene inserted in the reverse orientation (pcagTNF-alpha R) and normal saline (NS), pcagTNF-alpha R and INF-gamma and pcagTNF-alpha and NS, respectively. These results demonstrate an efficient approach for gene therapy of disseminated intraperitoneal cancer.

Effect of water content in perchloric acid on the non-aqueous potentiometric titration of nitrogen-containing compounds

In the United States Pharmacopeia (USP), 0.1 N perchloric acid in acetic acid volumetric solution (hereafter HClO4 VS) used for non-aqueous titration has specified a water content between 0.02 and 0.05%. Preparing this titrant with such a narrow range of water content is very time consuming, precludes the use of commercially available titrants, and, consequently, prompted an investigation to try and expand the range up to 0.5%. In this study, the titrimetric results obtained using HClO4 VS containing more water were very close to those obtained using the USP specified titrants. A maximum assay difference of 0.7% in the titrations of three selected nitrogen-containing compounds, clonidine hydrochloride, dipyridamole, and adenosine were observed. The titrimetric results obtained using these titrants were also precise with RSDs of not more than 0.4%. Therefore, a wider range of water content in HClO4 VS between 0.02 and 0.5% is suggested for the USP potentiometric titration of nitrogen-containing compounds.

Induction of the suicide HSV-TK gene by activation of the Egr-1 promoter with radioisotopes

In investigating new methods for the treatment of pancreatic cancer, we have explored the possibility of using a combination of radiation and gene therapies. We demonstrate herein that the early growth response gene 1 promoter (Egr-1) is sufficient to confer selective expression of the luciferase gene (Luc) in a human pancreatic tumor cell line (AsPc-1) when exposed to ionizing radiation. The Egr-1 promoter directed the radioinducible expression of luciferase, and yielded higher levels of Luc activity than that in nonirradiated lines. The radioisotopes Tc-99m, I-131, and Ga-67-citrate were selected as Egr-1 activators for their potential to accumulate in tumors. We studied Ga-67-citrate, a radioisotope employed in tumor scintigraphy, for its suitability for selective gene induction. The plasmid vector pEgr-1-Luc was transfected into AsPc-1 cells and then exposed to radioisotopes. Luciferase activity increased by 100-300 times over control. We also inserted the herpes thymidine kinase gene (TK) downstream of Egr-1 and transfected this construct into AsPc-1 cells. Ga-67-citrate and ganciclovir were added to the cells and cell survival was assessed by MTT assay. The growth of AsPc-1 cells transfected with the pEgr-TK construct was suppressed 2 days after exposure of the cells to Ga-67-citrate. The results indicate that Ga-67-citrate may be useful in combining radiation and gene therapies.

Evaluation of three individual glucosyltransferases produced by Streptococcus mutans using monoclonal antibodies

We previously established murine hybridomas producing a monoclonal antibody monospecific against three glucosyltransferases (I, SI and S) of Streptococcus mutans which contribute to dental caries formation. Here, we developed a new immunochemical technique (cross-dot system) with which individual levels of glucosyltransferases expressed by S. mutans can be evaluated. We also examined glucosyltransferase production and in vitro artificial plaque formation by a reference strain and several clinical isolates of S. mutans. The findings indicate that the levels of glucosyltransferases produced greatly vary with the cells and the culture medium, and that the cells producing high levels of both glucosyltransferase-SI and glucosyltransferase-I enzymes may possess high in vitro artificial plaque forming ability. We suggest that the cross-dot system will be useful for estimating the cariogenic potential of S. mutans isolates.

Degradation kinetics and isomerization of cefdinir, a new oral cephalosporin, in aqueous solution. 2. Hydrolytic degradation pathway and mechanism for beta-lactam ring opened lactones

Hydrolysis of cefdinir leads to pH-dependent isomerizations and beta-lactam ring-opening. Lactam ring opened gamma-lactones were produced as a mixture of four diastereoisomers based on the lactone methyl, and C-6 isomerizations in acidic to neutral solutions. Cefdinir and its 7-epimer were hydrolyzed to clarify the pathway leading to these lactones and the mechanism of C-6 epimerization with the aid of chiral separation techniques. Chiral separation using a bovine serum albumin column was employed to detect the beta-lactam ring opened products of cefdinir and its 7-epimer; the C-6 and C-7 isomerization was thereby observed; however, it was found to be pH-dependent at pH > or = 9. Optical activity detection applied to the lactones produced from cefdinir and its 7-epimer demonstrated that the corresponding peaks of these lactones were enantiomeric pairs. In addition, the smallest rate constant at pH 4 was observed for C-6 epimerization of the lactones, and it was found to proceed without deprotonation at C-6 by 1H-NMR spectroscopy. From the results of these studies, a plausible mechanism for C-6 epimerization has been proposed. Additionally, it was confirmed that two degradation pathways were involved during hydrolysis of cefdinir to the lactone.

Degradation kinetics and isomerization of cefdinir, a new oral cephalosporin, in aqueous solution. 1

Hydrolytic degradation products of cefdinir were studied in acidic (pH 1), neutral (pH 6), and basic (pH 9) solutions. Seven major degradation products were isolated by preparative and/or high-performance liquid chromatography and characterized by UV, IR, 1H-NMR, and mass spectra. To clarify degradation pathways in each pH solution, kinetic and product analyses during hydrolysis of cefdinir were carried out along with the followup reaction of representative degradation products. Cefdinir was shown to degrade via two major degradation routes: beta-lactam ring-opening and pH-dependent isomerizations (lactonization, epimerization at C-6 or C-7, syn-anti isomerization of N-oxime function).

Method development for the determination of cefdinir and its related substances by high-performance liquid chromatography

The validation of the HPLC method used for the determination of cefdinir and its related substances is described. The developed method was specific and stability-indicating and provided a linear response with concentration. The system and method precision, expressed as relative standard deviations, were not greater than 1%, and the reproducibilities within and between laboratories were acceptable for the assay method. The procedure can quantitate related substances greater than approximately 0.05% of the principal cefdinir peak.

[Chest wall reconstruction after the resection of primary chest wall tumors]

Between April 1983 and June 1994, we performed chest wall reconstructions on 9 patients (7 males and 2 females) out of 27 all of whom underwent the radical resection for the primary chest wall tumors. Histological diagnosis of tumors included 6 chondrosarcomas, 1 Ewing's sarcoma, 1 plasmacytoma and 1 giant cell tumor. Six lesions were located on the rib and 3 on the sternum. For the materials for reconstruction of the chest wall use a polyethylene plate in 2 patients, a Marlex mesh in 5 patients and a Marlex mesh with a methyl methacrylate utilizing the sandwich method in 2 patients. The polyethylene plate proved to be satisfactory for maintaining stability of the chest wall. However, our experience using this plate showed intensive foreign body reactions, and discovering these we have not use the polyethylene plate. Marlex mesh had an affinity with human tissue and was very easy to use and produced no complications. We use Marlex mesh for flat surfaces on the anterior or posterior chest wall. Marlex mesh and methyl methacrylate utilizing the sandwich method, combined the solidity and shaping of methyl methacrylate with the benefit such as easy fixation and excellent incorporation of the mesh.

[Two cases of empyema treated with rectus abdominis myocutaneous flap and muscle flap]

A rectus abdominis myocutaneous flap (RAM flap) has often been useful in breast reconstructions after the surgical therapy for breast cancer, or in other plastic surgeries. However, there have been few reports concerning about its applications for intrathoracic diseases. In this paper, we report two cases of recurrent empyema treated with RAM flap and muscle flap from rectus abdominis. One case is 75-year-old male with right-empyema and bronchial fistula after the thoracoplasty due to lung tuberculosis. The bronchial fistula was successfully closed with muscle flap from the right rectus abdominis. The other is 33-year-old male with left empyema and cutaneous fistula after the hemothorax due to traffic accident. He contracted with MRSA in his thoracic cavity. We resected the fistula and reconstructed his left chest wall with left RAM flap. The muscle flap from rectus abdominis or RAM flap has been very effective for the therapy of bronchial fistula after lung tuberculosis, and for the reconstruction of chest wall.

[Clinical experience with the CHAUX multi-purpose retractor]

We have performed dissection of the ITA using the CHAUX retractor in many patients. This retractor is a two-point sternal/IMA and valve retractor, with four sternal blades with individual and independent dual movement. The sliding sternal blade assemblies permit movement along the horizontal plane of the side arm. This retractor can be used for other types of cardiac surgery, as well. We obtained good results with its use for repair of distal aortic arch aneurysm. We conclude that this retractor is safe and useful for cardiac surgery.

Tautomeric phenomenon of a novel potent immunosuppressant (FK506) in solution. I. Isolation and structure determination of tautomeric compounds

Tautomeric phenomenon was observed in the HPLC chromatogram obtained from a novel potent immunosuppressant, FK506, in ethanol solution. Two tautomeric compounds derived from FK506 were isolated and purified by HPLC. Their structures were elucidated by spectral analyses. The mechanisms for this tautomerization were also established based on the results of structure analysis.

Quantitative mapping of the N-linked sialyloligosaccharides of recombinant erythropoietin: combination of direct high-performance anion-exchange chromatography and 2-aminopyridine derivatization

A rapid quantitative analysis of the sialylated N-linked oligosaccharides of recombinant erythropoietin (EPO) expressed in Chinese hamster ovary (CHO) cells has been developed. The procedure utilizes a glycoamidase (glycopeptidase F) to release all of the N-linked oligosaccharides from the native glycoprotein, followed by direct chromatographic analysis using high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection. The eight sialyloligosaccharides isolated from HPAEC were characterized by derivatizing with 2-aminopyridine followed by two-dimensional HPLC mapping of the pyridylaminated asialooligosaccharides (Tomiya et al., 1988, Anal. Biochem. 171, 73-90). Seven kinds of complex-type asialooligosaccharides were identified ranging from a biantennary structure to N-acetyllactosamine-extended tetraantennary structure. Approximately 3% of the terminal galactose residues of the oligosaccharides released from EPO were not sialylated whereas 97% contained an alpha(2-->3)-linked sialic acid. Quantitative oligosaccharide mapping of four different lots of EPO from CHO cells was performed to quantify the molar balance and distribution of the N-linked oligosaccharides. The sialyloligosaccharides were distributed with approximately 5% disialylated (single type), 20% trisialylated (six types), and 75% tetrasialylated (four types) oligosaccharides with an average molar recovery of 85% starting from 750 pmol of EPO.

De novo glucan synthesis by mutants streptococcal glucosyltransferases present in pellicle promotes firm binding of Streptococcus gordonii to tooth surfaces

Adherence of 3H-labelled cells of Streptococcus gordonii and Streptococcus milleri to artificial pellicles prepared from saliva supplemented with glucosyltransferases from mutants streptococci was examined using a new assay for sucrose-dependent cell-to-pellicle attachment. Results indicate that S. gordonii, but not S. milleri, could attach tightly to hydroxylapatite surfaces through de novo glucan synthesis by mutants streptococcal glucosyltransferases present in the experimental salivary pellicles.

[Treatment of pericardial cyst under thoracoscopy]

Thoracoscopic therapy was carried out on two cases of pericardial cyst. The first patient was a 24-year-old male. An abnormal shadow on a chest X-ray was pointed out at a regular checkup. Thoracoscopy was carried out under the local anesthesia and a thin-walled cyst was discovered. The cyst was punctured and serous fluid was aspirated. Then, several biopsy specimens were obtained from the cyst wall, a pathological diagnosis of the cyst was made as a pericardial cyst. One year after the thoracoscopy, no abnormal shadow is observed on chest X-ray. The second patient was a 26-year-old male. It was also discovered that he had an abnormal shadow on a chest X-ray at a regular medical checkup. Since a solid mass couldn't be completely denied, thoracoscopy was carried out in preparing for thoracotomy under the general anesthesia. The cyst observed between SVC and the azygos vein, and serous fluid was aspirated form the cyst. Following this, the cyst wall was biopsied and opened. Since no cases of malignant pericardial cysts have been reported, an operation is not usually required for these patients. We suggest that thoracoscopy is very useful tool for the final diagnosis and therapy of pericardial cyst because this method is easily carried out under local anesthesia.

The directions of static skin tensions in the face: their roles in facial incisions

The circular excisions of facial skin lesions were performed in 202 sites on 126 patients. The shapes of the resultant defects were observed to identify the directions of skin tensions in a static state. The round shapes remained in the forehead, temple, and nose. In the other areas of the face, the wounds were stretched in certain directions and became elliptical. The orientations of the facial static tensions were identical to the wrinkle lines in many facial areas. It is suggested that the wrinkle lines show the optimal directions of selective incisions in most facial areas except for the medial canthus and upper and lower lips.

[An evaluation of surgical treatment for giant bullae]

We have experienced 67 operative cases of giant emphysematous bullae of the lung. For the bilateral lesions, two stage operation was performed in five cases and one stage operation under median-sternotomy in 12 cases. Twenty six cases were subjected to Naclerio-Langer's method, 25 cases to partial resection or plication and 15 cases to lobectomy. At the earlier period lobectomy was the treatment of choice, but, recently lobectomy was avoided for the conservation of pulmonary function. In terms of the improvement of pulmonary function, there was no difference between Naclerio-Langer's method and partial resection by Autosuture. In conclusion, for the treatment of giant bullae, partial resection by Autosuture is preferable because of improvement of pulmonary function and one stage median-sternotomy for bilateral lesions also are effective.

The volume limitation of the galeal temporalis flap in facial augmentation

Galeal temporalis flaps based on the superficial temporal vessels have been used for facial augmentation and can be extended to the contralateral side beyond the midline in order to achieve maximum volume. In five patients, the volumes of extended galeal flaps were measured intraoperatively using a water displacement method. The calculated volume varied between 28 and 38 cm3. Experience with this flap showed satisfactory results with no complications; therefore, it is concluded that the extended galeal temporalis flap may be a first choice in the correction of facial soft tissue deficits less than 40 cm3. Clinical cases are presented.

[Influence of sucrose administration on blood insulin level, and number of insulin receptor and affinity on isolated hepatocytes]

In order to investigate the process to form diabetic-like condition by giving continuously excessive amount of sucrose, rats were maintained with purified water (Purified Water Group, PWG) and 10% sucrose solution (Sucrose Group, SG), as drinking solution, ad libitum for 5 months, and were subjected to the following experiments: 1) Serum glucose (BG) and insulin level (IRI) in sucrose tolerance test (STT) were measured periodically up to 24 hours after administration. 2) The number and affinity of insulin receptor on isolated hepatocytes from the rats of PWG and SG were also investigated. At the termination of the experiment, 5 months after the initiation, the BG and IRI levels in SG were significantly higher compared to those of PWG. In STT, SG showed reduced glucose tolerance and also high blood insulin level. The number of insulin receptor of isolated hepatocytes of SG was approximately 23% lower than that of PWG and the affinity of SG was slightly lower than that of PWG. These results suggest that continuous high BG and IRI levels are indicated in the rats given large amount of sucrose continuously. The number of insulin receptor of such rat was also reduced by down regulation, resulting in an insulin-resistance. These cause further high blood glucose level and abnormality in metabolism, to result in a prediabetic impaired glucose tolerance.

[Pharmacological study of kako-bushi-matsu: analgesic action and acute toxicity]

The analgesic effect and the acute toxicity of a medical drug "kako-bushi-matsu" (S-01), which was produced through several processing of raw aconite roots, were examined in comparison with those of ibuprofen, indomethacin and aspirin. S-01 (p.o.) inhibited the acetic acid- and phenylquinone-induced writhing dose-dependently. From the ED50 values, indomethacin showed more potent inhibitory action on the phenylquinone-induced writhing than on the acetic acid-induced writhing. Ibuprofen and aspirin showed the same tendency as indomethacin. The potency of the writhing inhibition by S-01 was almost to the same degree in both writhing methods. In the tail pressure method, S-01 raised the pain threshold ratio to almost the same degree as ibuprofen did. In Randall-Selitto's method, the analgesic effect of S-01 on inflamed foot was less than that of ibuprofen. In the normal foot, S-01 raised the pain threshold ratio dose-dependently, but ibuprofen did not influence the pain threshold ratio. On adjuvant-induced arthritic pain, S-01 and ibuprofen had an analgesic action, and this action of S-01 was less than that of ibuprofen. The oral LD50 value of S-01 was more than 10,000 mg/kg in mice and rats of both sexes. The above evidence indicates that S-01 has analgesic action and suggests that the mode of the analgesic action of S-01 may differ from those of ibuprofen, indomethacin and aspirin, which inhibit prostaglandin biosynthesis.

Time-course study of gastric damages in rats by anti-inflammatory drugs using a gastroscope and its quantification

Time-course studies on gastric damages in rats caused by nonsteroidal anti-inflammatory drugs (NSAIDs) were performed using a gastroscope, and the readings were quantified to obtain the Congestion-Hemorrhage Index (CHI) for evaluating the potencies of the damaging properties of NSAID. The correlation between CHI and Ulcer Index (UI), the quantified value obtained by the conventional methods, was highly significant at 6 and 24 hr after forced oral administration of NSAID. The peak CHIs of aspirin (300 mg/kg), indomethacin (60 mg/kg), mefenamic acid (300 mg/kg) and fenoprofen calcium (300 mg/kg) appeared approximately 24 hr after a single forced oral administration of drugs. Thus, it was suggested that an observation at 24 hr in addition to one at 6 to 7 hr might be necessary for the examination of damaged gastric mucosa. Under the present experimental conditions, fenoprofen calcium caused the greatest damages on gastric mucosa among the four NSAIDs. Mefenamic acid showed the least damaging potency on gastric mucosa, having a smaller CHI than that of aspirin. Indomethacin possessed a stronger damaging property than aspirin.

Hypertrophy of labia minora in myelodysplastic women. Labioplasty to ease clean intermittent catheterization

Female myelodysplastic patients are sometimes annoyed by hypertrophy of the labia minora, possibly caused by long-term diaper dermatitis. This condition makes intermittent catheterization difficult and impairs the cleanliness and aesthetic appearance of the external genitalia. We successfully performed labioplasty on 3 myelodysplastic females.

Anterolateral leg island flap

Three anterolateral leg island flaps based on the septocutaneous vessels of the anterior crural intermuscular septum were successfully transferred. The anterolateral leg island flap is thin, reliable and relatively easy to raise. It is extremely useful for covering the knee and the upper half of the leg.

Reverse-flow island flap: clinical report and venous drainage

Twenty-two reverse-flow island flaps were transferred. These included peroneal, forearm, anterior tibial, and temporal flaps. Sixteen of 22 flaps survived completely. We encountered partial necrosis in 4 flaps and total necrosis in only 2 flaps. We credit this success to the reliability and availability of the peroneal, forearm, and temporal flaps; but we do not encourage use of the anterior tibial flap. The flaps that survived well did not show any signs of venous congestion. The advantage of the reverse-flow island flap is that it can be transferred from a proximal to a distal location. Using cadavers and fresh amputated limbs, studies on venous drainage of the reverse-flow island flap were performed. The venae comitantes had numerous venous valves and communicating branches, but more than sufficient reflux of the venous blood occurred through the valves at pressures of 90 to 105 cmH2O. We believe that the venous drainage of the reverse-flow island flap occurs as a result of reflux actions at the valve, communicating branches between the venae comitantes, and bypass vessels around the valves.

Degradation kinetics and mechanisms of a new cephalosporin, cefixime, in aqueous solution

Hydrolysis of cefixime in buffer solutions (pH 1-9) at 25 degrees C and a constant ionic strength of 0.3 was investigated using ion-pair reversed-phase HPLC. Hydrolysis rates followed pseudo first-order kinetics; the rate of hydrolysis of cefixime was very slow at pH 4-7, slightly faster at lower pH, and quite rapid at higher pH. In the early stages of hydrolysis, six major degradation products were isolated and identified: a beta-lactam ring-opened product and a 7-epimer (basic conditions), three lactones derived from intramolecular cyclization between the 2-carboxyl and 3-vinyl groups (acidic conditions), and an aldehyde derivative involving a 7-acyl moiety (neutral conditions). Principal degradation pathways for cefixime were found to involve initial cleavage of the beta-lactam ring.